Causes of Delay in Power Transmission Projects: An Empirical Study

: Power transmission (PT) projects are vital for the power sector. However, worldwide PT projects experience delay. There is an urgent need to understand the unique causes of delays in PT projects. This paper presents the ﬁrst empirical study on causes of delays in PT projects via a comprehensive literature review. Based on this literature review, 63 potential delay factors are identiﬁed and divided into ten major groups. These include two new groups of delay attributes, comprising sector-speciﬁc factors (SSF) and general factors (GF), where SSF pertains solely to PT projects and GF contributes to minimizing the bias of project participants. A questionnaire survey of 311 PT stakeholders is conducted to determine the overall ranking of the delay factors using the relative importance index. The results indicate that SSF, GF, and external / unavoidable factors are the most critical groups of delay factors, with the top-ranked factors being right of way problems of transmission line (TL), frequent changes in TL routes, and accessibility to the TL tower locations. Finally, recommendations are made to help minimize time overruns in PT projects, as well as in other linear power and non-power construction projects in general.


Introduction
Since the industrial revolution, power has been the mainstay of development of modern civilization. The demand for electric power in the modern world is increasing rapidly and is predicted to almost double by 2040 from 2014 [1]. Besides the traditional resources, the recent contributions from the renewable energy sources are significantly subsidized to the achievement of forecasted 40,000 TWh (terawatt hour) power generation in 2040 [1]. Studies show that power transmission (PT) and power distribution system losses are more than 15% of the generated electricity [2]. Hence, a reliable and functional PT network, an essential link between power generation and distribution, is required to transmit the forecasted generated power to the consumer because most of the power generators are stationed far from the developed regions [3]. In order to streamline the smooth transmission of the generated forecasted electricity to the distributors and/or customers, it is clear that the world will see a significant increase in PT projects in the near future. Most of the countries in the world are very keen to complete their power sector projects in time and, hence, timely completion of PT projects is crucial, because without a reliable PT link, power generation and distribution systems are effectively disabled. Moreover, development partners offer flexible soft financial support for the PT sector development, but the planned benefits are partially or never realized due to the frequent delay in PT projects completion [4]. Therefore, the timely completion of PT projects can significantly contribute to the betterment of human civilization by making electricity accessible whenever and wherever it is needed. Since a significant time is spent during the construction phase of a PT project, it is realistic to expect that most delays occur in this stage. It is logical, therefore, to study the causes of delays in construction projects, and most specifically non-power linear projects, as foundational in finding causes of PT project delays [5]. The applicability of the factors causes delays in power generation vis-à-vis PT projects increases further than linear construction projects, as these projects consist of the construction of stations and substations that also exist in PT projects [5]. Power distribution projects have not only the stations/substations, but also the powerlines and, hence, PT projects are closer to power distribution projects than power generation projects [5]. Of the total of 86 published studies related to causes of delay, 83 papers are related to nonpower linear construction projects, power generation projects provide two papers [17,18], and power distribution projects provide one paper [19]. The non-power linear projects include: construction of buildings (20 papers) [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39], petrochemical construction (one paper) [40], construction of oil and gas lines (two papers) [41,42], railway construction (one paper) [43], highway/road related construction (eight articles) [44][45][46][47][48][49][50][51], and other construction projects (51 papers) . Based on the above studies and a content analysis of the factors related to delay revealed from the literature review, as shown in Appendix A, this study recommends nine groups to include all delay attributes of a project. That is Since a significant time is spent during the construction phase of a PT project, it is realistic to expect that most delays occur in this stage. It is logical, therefore, to study the causes of delays in construction projects, and most specifically non-power linear projects, as foundational in finding causes of PT project delays [5]. The applicability of the factors causes delays in power generation vis-à-vis PT projects increases further than linear construction projects, as these projects consist of the construction of stations and substations that also exist in PT projects [5]. Power distribution projects have not only the stations/substations, but also the powerlines and, hence, PT projects are closer to power distribution projects than power generation projects [5]. Of the total of 86 published studies related to causes of delay, 83 papers are related to nonpower linear construction projects, power generation projects provide two papers [17,18], and power distribution projects provide one paper [19]. The non-power linear projects include: construction of buildings (20 papers) [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39], petrochemical construction (one paper) [40], construction of oil and gas lines (two papers) [41,42], railway construction (one paper) [43], highway/road related construction (eight articles) [44][45][46][47][48][49][50][51], and other construction projects (51 papers) . Based on the above studies and a content analysis of the factors related to delay revealed from the literature review, as shown Energies 2020, 13, 17 4 of 29 in Appendix A, this study recommends nine groups to include all delay attributes of a project. That is administrative/corporate-related issues, employer/owner-related issues, contractor-related issues, consultant-related issues, drawing-related issues, materials-related issues, equipment-related issues, labour/worker-related issues, and external/miscellaneous issues. The summarised delay factors from Appendix A are presented in Appendix B under the above mentioned groups, including some modifications based on experts' recommendations during a preliminary survey.
The literature review indicates that late procurement of special construction equipment, unavailability of its spare parts, and its late delivery at site cause significant delay in power generation projects, which is not pertinent to general non-power linear construction projects [5]. Hence, these outcomes indicate that the causes of delay of non-power projects do not account for all those factors related to power generation projects, some of which are related only to power generation projects and possibly PT projects. In addition, power distribution line construction gets delayed due to the interference with other construction projects, such as road/highway construction, building construction, and PT line construction. However, low-voltage power distribution lines generally cross various administrative borders and hence face more regulatory and public/political issues. It is clear, therefore, that the factors causing delay in power generation and non-power linear projects do not include all those factors associated with power distribution projects, some of which are applicable only to power distribution and possibly PT projects [5]. It is investigated that PT projects are likely to have their own unique causes of delay beyond non-power construction, power generation, and power distribution projects, and hence need urgent empirical investigation [5].

Study Setting
Bangladesh has much in common with the rest of world in terms of its power requirements, including the expansion of its industries, agricultural work, workforce, healthcare, and significant development in communications, resulting in an ever-increasing demand for power [103]. Realizing the importance of the faster expansion of power systems for future social and economic development, the government of Bangladesh (GoB) aims to more than double the country's 2010 power generation by 2021 according to its Power Sector Master Plan (PSMP) [104]. The GoB has increasingly funded the power sector, with power projects allocated more than 15% of the annual development program (ADP), as shown in Figure 2a [105]. In the 2015-16 financial year, the contribution of power was 1.45% of Gross Domestic Product (GDP) [106]. In support of this, the PSMP also recommends the expansion and development of PT infrastructure to cope with the enhanced power generation [104]. The GoB's initiatives are also supported by the development partner Asian Development Bank (ADB), and ADB states that the rapid economic growth in Bangladesh at 6% a year during 2005-2010 is causing electricity demand to increase exponentially. As such, the GoB is trying to reduce the gap between generation and demand [107,108]. In addition to GoB funding, total private sector investment, from 2014 to 2030, is projected to be around USD 22.3 billion, which is almost half the GoB funding [109]. In order to obtain the best use of these funds, Bangladesh is exploring the electricity sources within and across its borders. For example, Bangladesh already imported electricity from India and there are also ongoing processes to purchase electricity from other neighboring countries (i.e., Myanmar, China and other south Asian countries) [110,111]. The GoB has also announced the necessity for around USD 20 billion investment to expand associated PT projects [109]. Furthermore, Bangladesh has started to procure a nuclear power plant [112], and the GoB has also targeted solar energy to be 10% of total generation [113]. These initiatives have resulted in a significant increase in power generation capacity from 4942 megawatts (MW) in 2009 to 12,780 MW in 2016, and in this period, per capita generation of power also increased from 220 kilowatt-hours (kWh) to 380 kWh [106]. According to the GoB master plan, power generation will increase to 24,000 MW in 2021 and 40,000 MW in 2030 [106]. To keep pace, the relevant authority in Bangladesh-a public limited company solely responsible for the development, operation, and Energies 2020, 13, 17 5 of 29 maintenance of the national grid-has committed to construct around 10,513 circuit kilometers of TLs and 160 substations (SSs) at different voltage levels during 2016-2021 [114].  This trend in PT system development, in conjunction with the increase in power generation, is also evident from Figure 2b, and indicates a proportional development in PT projects with power generation [114]. Hence, there will be a noteworthy surge in the number of PT projects in the near future to ensure the timely transmission of the generated electricity. Despite the criticality of upcoming PT projects, approximately 80% of these foreign-aided development projects are currently delayed in Bangladesh, resulting in financial losses and hindering planned development [115]. As such, Bangladesh provides a fertile context upon which to conduct this first-ever empirical study into the causes of PT project delay.

Data Collection
Beyond the nine groups of delay causes mentioned in the updated literature review section, PT projects comprise a number of causes unique to PT projects and not found in power generation, power distribution, or other non-power linear projects [5]. Hence, as a part of the first objective in this study, we develop the groupings presented by Pall et al. (2016) [5] to account for PT sector-specific factors before proceeding to address objectives 2 and 3, which concern testing the relevancy and adequacy of the delay factors.
To do this, a two-stage questionnaire was used to collect data for this study. A preliminary questionnaire was developed for the first stage, containing five sections (respondent's general information, case project details, factors contributing to the case project delay, the group effect on the case project delay, and further comments). Section 1 of the questionnaire elicited such demographic information as experience with PT project work, professional background, and most recent affiliation type (owner/contractor/consultancy). Section 2 detailed the specification of a specific case project (i.e., "the case project") most familiar to the respondent, which was either most delayed or least delayed in last five years, about which the answers from the respondent are based. Additionally, the respondents answered questions concerning the type and scope of the project, contractual and actual project duration, voltage level of TLs and SSs, again, all in relation to the case project. Section 3 asked how much each factor contributed to the delay of the selected case project. This response was based on a five-point Likert scale from 1 (very minor contribution) to 5 (very major contribution), with additional 'no effect' and 'don't know' options [116]. Section 4 evaluated the most critical individual group of factors contributing towards the case project delay, while Section 5 requested "further comments" in the form of other factors not mentioned in the questionnaire (i.e., not revealed from the literature review) that potentially contributed to the delay of the participant's case project. In this first stage, expert contacts were collected online (www.pgcb.org.bd) and by personal communications. Participants were selected randomly from each category and the questionnaire sent by email and/or online survey portal. Ten questionnaires were sent to both the employers and contractors and five to the consultants. In total, 18 completed responses were returned, comprising seven owners, eight contractors, and three consultants. The responses from the owners comprised three project directors having minimum 15 years' experience, and two executive engineers, one executive technical director, and one manager from the project This trend in PT system development, in conjunction with the increase in power generation, is also evident from Figure 2b, and indicates a proportional development in PT projects with power generation [114]. Hence, there will be a noteworthy surge in the number of PT projects in the near future to ensure the timely transmission of the generated electricity. Despite the criticality of upcoming PT projects, approximately 80% of these foreign-aided development projects are currently delayed in Bangladesh, resulting in financial losses and hindering planned development [115]. As such, Bangladesh provides a fertile context upon which to conduct this first-ever empirical study into the causes of PT project delay.

Data Collection
Beyond the nine groups of delay causes mentioned in the updated literature review section, PT projects comprise a number of causes unique to PT projects and not found in power generation, power distribution, or other non-power linear projects [5]. Hence, as a part of the first objective in this study, we develop the groupings presented by Pall et al. (2016) [5] to account for PT sector-specific factors before proceeding to address objectives 2 and 3, which concern testing the relevancy and adequacy of the delay factors.
To do this, a two-stage questionnaire was used to collect data for this study. A preliminary questionnaire was developed for the first stage, containing five sections (respondent's general information, case project details, factors contributing to the case project delay, the group effect on the case project delay, and further comments). Section 1 of the questionnaire elicited such demographic information as experience with PT project work, professional background, and most recent affiliation type (owner/contractor/consultancy). Section 2 detailed the specification of a specific case project (i.e., "the case project") most familiar to the respondent, which was either most delayed or least delayed in last five years, about which the answers from the respondent are based. Additionally, the respondents answered questions concerning the type and scope of the project, contractual and actual project duration, voltage level of TLs and SSs, again, all in relation to the case project. Section 3 asked how much each factor contributed to the delay of the selected case project. This response was based on a five-point Likert scale from 1 (very minor contribution) to 5 (very major contribution), with additional 'no effect' and 'don't know' options [116]. Section 4 evaluated the most critical individual group of factors contributing towards the case project delay, while Section 5 requested "further comments" in the form of other factors not mentioned in the questionnaire (i.e., not revealed from the literature review) that potentially contributed to the delay of the participant's case project. In this first stage, expert contacts were collected online (www.pgcb.org.bd) and by personal communications. Participants were selected randomly from each category and the questionnaire sent by email and/or online survey portal. Ten questionnaires were sent to both the employers and contractors and five to the consultants. In total, 18 completed responses were returned, comprising seven owners, eight contractors, and three consultants. The responses from the owners comprised three project directors having minimum 15 years' experience, and two executive engineers, one executive technical director, and one manager from the project finance division having a minimum of 12 years' experience. Five senior international and three national contractor personnel responded, each having worked over 20 years as a PT project manager. Two international and one national consultant also responded, with 15 years or more experience in PT projects. Furthermore, 11 Bangladeshi, two Indian, one German, one Spanish, one Korean, and two Chinese experts participated in the preliminary survey.
As a result of the experts' strong recommendations, a new and unique group of delay factors was introduced into the final questionnaire: namely, 'sector-specific factors (SSF)'. The SSF group contains the causes of delays that are applicable to PT projects and are listed as Group 1 in Appendix B. The sector experts' opinions also suggested a new group of factors to minimize respondents' bias. This was based on the extraction of factors common to the project owner, contractor, and consultants, due to their collective responsibility for such matters as drawing related issues where, in a turnkey contract environment, owners are responsible for the approval, contractors are usually accountable for designing, drafting, and submission, and consultants provide comments and recommendations on the submitted drawings. This resulted in a second new group of 'general factors (GF)' and the deletion of group 5: Drawing related issues of the literature reviewed by Pall et al. (2016) [5].
The final questionnaire was developed in the second stage based on the comments and feedback from the 18 PT sector experts surveyed in the first stage. This was essentially the same as the preliminary questionnaire, but with the PT-specific and project parties' (i.e., owners, contractors, and consultants) general factors redistributed to the GF groups as summarized and coded in Appendix B. Group 9: External/miscellaneous was renamed as 'Group 10: External/unavoidable factors'.

Data Analysis
The data were collected via both online and hard copy questionnaires in accordance with the ethical requirements for research involving humans developed by Australia's National Health and Medical Research Council [117]. This data was analyzed using SPSS 25 and MS Excel for ranking the factors overall and by the three groups of project parties (employer, contractor, and consultant) using a relative importance index.
The diverse profile of respondents and projects greatly assists in establishing the relative importance of the various factors responsible for PT project delay. The means and standard deviations are not appropriate measures for evaluating the overall relative importance (ranking) of the delay factors, as they do not consider the relationships involved [83]. Instead, the Relative Importance Index (RII) is often used to rank the causes of delays [29], with where i denotes the response category index, a i denotes the weight of the response for category i, x i is the frequency of the response for category i, and N is the total number of respondents. The values of RII, therefore, range from 1 to 5, with the higher RII value indicating a higher rank. Cronbach's alpha (Cα) is used to test the internal reliability consistency. This is a popular and powerful method to estimate the reliability of a construct/group for a confirmatory factor approach to summarize the information contained in the group [118]. The Cα reliability test is also used to judge the appropriateness of the delay factors in a group and the Cα values range from 0 to 1, with a value close to 1 indicating greater internal reliability [63]. Doloi (2009) suggests a frequently used rule of thumb of Cα > 0.90 as excellent, 0.90 > Cα > 0.80 as good, 0.80 > Cα > 0.70 as acceptable, 0.70 > Cα > 0.60 as questionable, 0.60 < Cα > 0.50 as poor, and Cα < 0.50 as unacceptable [119]. Spearman's rank order correlation (SROC) coefficient is used to test the significance of the correlation between the factors in each group and examine the degree of agreement between the project parties. SROC is a distribution-free or nonparametric test and thus does not assume homogeneity of variance and is not influenced by outliers as it compares medians [59]. SROC coefficients (rho) range from +1 to −1, where close to +1 indicates a strong positive relationship/agreement, close to −1 means a strong negative relationship/agreement, and close to 0 means a weak or no relationship/agreement. This study uses the following formula to calculate the SORC [59]: where ρ s is the Spearman rank correlation coefficient between two project parties, d is the difference in rank between two variables for a single delay cause, and n is the number of rank pairs.

Response and Respondents' Profile
A wide range of respondents was targeted to obtain a representative sample of the population [74]. Therefore, data were collected from all levels of PT project professionals (national or international) who are still working and/or have worked in Bangladesh. Table 1 contains a summary of the respondents' profiles, which indicates a good mix in terms of the experience and expertise of the project parties. The list of the participants was prepared by using employee lists from related organizations websites (www.pgcb.org.bd; www.bpdb.gov.bd). Introductory conversations and online contacts were made with the respondents to explain and clarify the objectives of the study and content of the questionnaire. A total of 532 experts were approached and 339 responses were obtained, constituting a 63.72% response rate. Of these, 28 responses were considered incomplete because of missing data, especially in the extensive choice of 'no effect' and 'don't know'. The remaining 311 responses were used in the analysis that follows. Data collection was based on a broad spectrum of PT project management personnel, comprising employers, national and international contractors, and consultants. The majority of the respondents (72.30%) are Bangladeshi, working nationally and internationally in PT projects, followed by 10.50% Indian, 4.90% Chinese, 4.5% German, 4.2% Spanish, and 3.60% Korean respondents.
As shown in Table 1, the majority of respondents are owners and contractors, with a very small number of consultants. Approximately 50% have more than 10 years' experience in PT project management. In terms of profession, over 33% are executive engineers (EE) working as owners' project managers or contractors' project managers (PM), with a further 25% being owners' sub-assistant Engineers (SAE) and contractors' project engineers (PE) mainly working on site. The other major group of respondents comprises owners' superintending engineers (SE) working as project directors and contractors' project directors (PD), and all of whom have considerable knowledge of PT project implementation. The results are therefore informed by a very deep knowledge of PT projects delay in Bangladesh. Moreover, samples show that more than 60% of the projects have been delayed for more than six months.

Ranking and Correlation of the Delay Factors
Appendix C provides the delay factors ranked by the RII and arranged according to their groups, as provided in Appendix A. Individual delay factors and delay groups are ranked based on individual and the overall project parties' view. The critical individual and group delay factor rankings are also presented in Table 2, as shown below.  The overall Cα value of the factors is 0.927 and the Cα values of the groups are greater than 0.8, indicating a good level of internal reliability consistency. The SROC correlations between the factors under each group are shown in Appendix D and are described later in this section along with the ranking of the delay factors.

Factors Contributing to PT Project Delay
Typically, PT projects across the world consist of SS and high voltage TL that carry power from distant power sources to demand centers [120]. The essential consideration of the TL voltage (electrical induction) makes the PT projects significantly different from any other projects. TL can be hundreds of kilometers long, which makes it difficult to obtain a RoW without any problems. As with RoW, the voltage level and electrical induction properties of the TL make the route changing remarkably different from other projects. Furthermore, the overhead TL (OHTL) construction requires special technical considerations when crossing existing TLs and other infrastructures, such as railways, roadways, and telephone lines, which can result in significant time overruns. TL construction usually starts from the middle of the route and approaches towards the substations at both ends. With any significant change in the substation's gantry or dead-end tower positions, the TL route needs to shift from its planned direction, which demands the drawings are changed and technical considerations, which, in turn, prolong the delay. Moreover, the construction timing of dead-end towers of the TL or hook-up gantries of substations can adversely affect project completion and is unique to PT projects. The TL is usually routed through open fields away from localities and infrastructures, but does require sophisticated equipment for its construction, erection, and stringing; these issues (especially erection and stringing) are significantly different from any other projects. The river crossing tower construction of the TL is not usually found in any other construction projects. TL tower erection and stringing, including the remote discrete tower foundation construction, render the logistic support of the supervision team critical. Generally, supervision of the construction, erection, and stringing of the tower foundations on hills or in water necessarily demands a wide range of logistic support to deliver the works smoothly. In addition, the remote SS location, electrical properties of the sophisticated equipment involved, and the big/heavy transformer installation at the SS, make considerations of Project delay is defined as the additional time involved in completing a project beyond its contractual duration. A delay is a situation in which a contractor, consultant, or client/owner jointly or independently contribute to the delay of a project's completion time [121]. The five major causes of delay in PT project management considered by each project party are presented in Table 3, which reflects the uniqueness of PT project management. The groups and associated delay factors are discussed below in the light of the existing studies and the expert opinions collected during the preliminary survey under Section 5 of the preliminary questionnaire. As Table 3 shows, the 'right of way (RoW) problems of the transmission line' or SSF1 (RII = 3.585) is ranked as the most critical factor contributing to PT project delay in both the individual and combined view of the project parties. This is because RoW problems are very unpredictable and common in PT projects, and also known to all the project parties. The RoW is a strip of land along the TL having the same width on both sides of the TL centerline [5]. The minimum RoW width is approximately 20 m for the overhead TL (OHTL) and increases with the increase in TL voltage level, and RoW not applicable for underground TL [122]. RoW problems have many unknown dimensions, from regulatory issues to changes in land demographics. Regulatory acts prohibit TLs from crossing existing structures, i.e., educational institutions, religious establishments, graveyards, forests, market places, and households [123]. The RoW may have to be altered because of a sudden change in river courses, unpredictable ground conditions (i.e., sand boiling), and sudden flooding along the TL routes. There is also no compensation for the RoW in most countries, which is one of the critical issues prolonging delays, as many landowners try to hinder TL construction as it often leaves their land unusable for future development. Moreover, due to the lack of any incentives, landowners sometimes intentionally build settlements in the RoW just before the TL construction starts on site, which can substantially affect the completion time because of the lengthy legal procedures involved which can be found in linear road construction projects [44,45].
Second overall in the SSF group, and quite close to RoW, is 'frequent TL route changes' (SSF3) at RII = 3.495. This ranking is agreed by the project parties except for the contractors, who rank it third.
Mainly contractors approach route changes and owners with recommendations from consultants to approve or reject the route after due audits. Route changes can occur primarily due to RoW problems, followed by the erroneous route surveys, public resistance, and other unavoidable circumstances. The type of contract also affects route changes, as contractors prefer to take the shortest route to increase their profit margin and hence are inclined to keep changing routes.
Ranked third overall in the SSF group at RII = 3.371 is 'accessibility to the TL tower locations' (SSF5), with the owners ranking this higher than the other two project parties. Transporting construction and other materials to the tower location presents a major challenge that can become extreme when the TL runs across water bodies and hilly areas. Sudden floods or heavy rains can also interfere with access to the tower locations and delay the project. The location of the TL dead-end tower depends on the hook-up gantry position of SS, and SS and TL contracts are generally awarded to different contractors. If the SS contractor changes the SS layout significantly because of difficulties or errors, it creates massive dismantling work (foundations and towers) for the TL contractors and can prolong project completion time for years. Hence, SSF2 is a critical issue ranked third (RII = 3.500) by the consultants, while the ranking of the other parties is less critical.
Overall, the SSF attributes group is the most critical and hence ranked as first, both individually and collectively, see Table 2. The factors in the SSF group have good reliability (Cα = 0.905) and are significantly correlated, as shown in Appendix D.

General Factors (GF)
'Poor communication and coordination between the project parties' (GF1) is very apparent across all kinds of projects [41]. Consistent with Sambasivan and Soon and other studies, Table 3 indicates that GF1 is also a major delay factor [69,74]. Collectively GF1 (RII = 3.363) is evaluated as the 4th most critical overall, with the owners, contractors, and consultants individually assigning it 8th, 5th, and 6th place, respectively. Poor communications compromise the effective coordination of project stakeholders, which leads to increased rework and hence delay. This generally occurs due to the insufficient flow of information. Of all the stakeholders involved, project managers are the key point of contact, and hence their negotiation skills significantly affect coordination and thus project progress.
'Delay in payments' (GF4), at RII = 3.357, is the 5th most critical factor as shown in Table 3, indicating the importance of the funding capabilities and payment procedures of all the project parties because of being a chain between the two main project parties. In alignment with existing literature, this also emphasizes the liquidity of the project stakeholders and the need to pay special attention to smooth disbursements to reduce delay [24]. It is often not the funding, but the lengthy bureaucratic procedures that delay the owner's payments and thus impede physical progress by making it difficult for the contractor to achieve planned progress. Hence, while the contractors rank GF4 the 2nd most critical, it is ranked 7th by the owners and consultants.
Corresponding with existing findings, 'Drawing and/or design related problems' (GF9), ranked 6th overall at RII = 3.354, is also of major importance as shown in Table 3. In a turnkey contract environment, consultants play a vital role in drawing design-related issues, and their skills determine the quality of their work [35]. Unclear owner specifications and erroneous contractor designs complicate the situation and hamper expected progress [80]. As final victims, contractors and owners both rank this (GF9) as 4th out of their top five factors, while the consultants, being less affected, rate it 8th. Moreover, 'Improper site management and supervision' (GF5) and 'poor planning and scheduling' (GF6) of the GF group are ranked as 9th and 11th respectively. With four factors in the top 10, this indicates the criticality of GF. Hence the overall (RII = 3.328), owners (RII = 3.295), and contractors (RII = 3.464) ranking of GF is 2nd out of 10 groups, as shown in Table 2. The Cα value of the GF group is 0.882, and significant correlations exist between the factors as shown in Appendix D.

Administrative Factors (AF)
The 'approval processes of government agencies' (AF2) is the critical delay factor in the AF group with an overall 15th rank (RII = 3.045) and with contractors ranking it as 14th (RII = 3.155) as listed in Appendix C, which aligns with the findings of Doloi and others [52,84]. Owners and consultants rank AF2 as 16th and 29th, respectively, because the owner's project execution division wants to disburse payment quickly, but fail due to the lengthy certification process from the owner's other related departments and consultants are usually financially solvent, with less liabilities to pay contractors. The internal consistency reliability of AF is significant (Cα = 0.868) and Appendix D exhibits significant correlations between the delay factors.

Employer/Owner-Related Factors (E_ORF)
This group is collectively ranked as 4th of the 10 groups as shown in Table 2. Owners and contractors both also rank E_ORF as 4th, while consultants rank it 3rd. 'Approval processes of project documents' (E_ORF4) is the most critical factor in this group and jointly ranked 8th (RII = 3.251). Prompt approval of project documents is important for the progress of the project but can be a lengthy organizational process that can become even lengthier when less experienced professionals are involved [73]. E_ORF4 is also rated 9th (RII = 3.202), 6th (RII = 3.391), and 5th (RII = 3.250) by the owners, contractors, and consultants, respectively. E_ORF has significant Cα value (0.801) and the factors in this group have strong correlations as shown in Appendix D.
'Owner-demand change orders (E_ORF1)' of this group is significantly different from the 'changes in the scope of works (E_ORF5)' because E_ORF1 changes initiated by the employers and the E_ORF5 arise because of unavoidable technical issues occurring during implementation and the urgency associated with solving the problems by all the project parties. Moreover, any delays in the payment of the customs duty and value-added tax for importing equipment (E_ORF2) is the sole responsibility of the employer and beyond the usual contract prices between the project parties.

Contractor-Related Factors (CRF)
The contractor is of the utmost importance for completing any project on time. 'Inadequate experience of contractors' (CRF2) is the most critical factor in this group, with the owners and consultants ranking it 5th and 10th respectively as shown in Appendix C. CRF2 is mainly attributed to the contract awarding process because the lowest bidder is awarded the project irrespective of its experience [36]. While Cα = 0.902 indicates good reliability of the group, Appendix D indicates significant correlations between the factors.

Consultant-Related Factors (ConRF)
The ConRF group does not directly contribute to delay because consultants only coordinate with owners for the smooth execution and are less accountable for timely completion. In a design-built turnkey (DBT) contract environment, as already stated, consultants are not liable for the approval process, but rather provide comments, recommendations, and technical assistance to the owner. From this group, 'Late comments on design and/or contract scope' (ConRF1) is collectively ranked as 31st-a ranking also supported by the owners and contractors, whereas consultants ranked it as least critical (54th) as shown in Appendix C. However, the factors in ConRF group are the most reliable (Cα = 0.925) and strongly correlated as listed in Appendix D.

Materials-Related Factors (MRF)
The contractor is mainly responsible for this group in a turnkey contract environment and the overall ranking is 5th, while the owners and consultants rank it 6th and 8th respectively as shown in Table 2. The overall critical items from this group is 'construction materials shortage on-site' (MRF1) followed by 'delay in materials delivery to site (MRF2)', with corresponding overall rankings of 23rd and 27th as shown in Appendix C. The consultants disagree with the overall observation, indicating that MRF2 is more critical than MRF1, due to the shipment of materials from overseas [36]. The reliability (Cα = 0.827) and correlations between the factors in the group MRF are statistically significant as shown in Appendix D.

Equipment-Related Factors (ERF)
Unexpectedly, the contractors rank this group more critical than others, as they are mainly responsible for the supply of equipment for DBT projects [124]. Overall, the most critical item in this group is the 'lack of modern equipment' (ERF4) followed by the 'shortage of civil and mechanical equipment' (ERF1). Foreign turnkey contractors usually subcontract the construction work to local civil contractors who cannot afford modern sophisticated equipment. The reliability of the factors in ERF is 0.803, and the correlations are significant for this group, as shown in Appendix D.

Labor/Worker-Related Factors (L_WRF)
Being ranked 10th, this group is the least critical of all 10 groups, although the consultants rank it as 9th as shown in Table 2. 'Availability of skilled labor' (L_WRF2) is critical but no other factors in this group are significant because of the readily available labor in Bangladesh. Statistically, the group factors are reliable (Cα = 0.809) and they have good correlations, as seen in Appendix D.

External/Unavoidable Factors (E_UF)
This group is one of the most critical. The overall (RII = 3.186), owners (RII = 3.171), and contractors (RII = 3.191) rank this group as 3rd, but the consultants (RII = 3.500) rank E_UF as 2nd, more critical than other project parties, as provided in Table 2. The most critical factor in this group is 'political interventions' (E_UF9) in the form of strikes and blockades. Bangladesh suffers transport interruptions frequently due to strikes, which adversely affects the storage of construction materials on-site arriving from distant sources, and the delivery of the equipment from ports to site prolongs delays [125]. Considering the unavoidable nature of E_UF9, the owners (RII = 3.482) and consultants (RII = 3.375) rank this as 3rd and 4th, respectively, while the contractors and overall ranking of E_UF9 is 7th. The overall (RII = 3.235) and owners' (RII = 3.197) ranking for 'heavy rain or floods' (E_UF1) is 10th [59] and also the other parties agree with the severity of this item, ranking it 11th and 13th by the consultants and contractors, respectively. According to all the parties, E_UF1 is followed by 'local public resistance' (E_UF8) and 'unforeseeable ground conditions' (E_UF5), respectively. This group has significant internal reliability (Cα = 0.817) and the correlations between the factors in this group are substantial, as seen in Appendix D.

Agreement between the Project Parties
This study uses Spearman's correlation coefficient to summarize the strength and direction (negative or positive) of agreement between two project parties. It is evident from the analysis that owners and contractors have the strongest agreement (0.929 ** ) in ranking the delay causes, followed by the agreement between owners and consultants (0.776 ** ) and between contractors and consultants (0.726 ** ), as shown in Table 4. Moreover, the agreement between the project parties is significant at the 0.01 level. As described earlier, this study introduced a new group, GF, that contains factors involving the responsibilities of all the project parties to obtain less biased responses. The GF group significantly reduces the factors from the project parties labelled groups (E_ORF, CRF and ConRF), resulting in an extremely strong agreement between the project parties that is also evident from Figure 3.   Figure 3a shows the strong agreement between the project parties in ranking the overall top 10 delay factors as summarized in Table 2. Noticeably, overall, employers and contractors are close in ranking the top 10 delay factors in PT projects. Moreover, the most critical five factors both overall and in view of the individual project parties from Table 3 are presented in Figure 3b, and support a close agreement in ranking the critical factors. While both overall and other project parties almost coincide, the consultants rank a few factors differently. Figure 3 Figure 4 illustrates how this study contributes to advancing not just our understanding of delays in PT projects, but also our understanding of delays to power distribution, power generation, and non-power linear construction projects worldwide. With regard to PT projects, the study provides the first evidence of a unique group of delay factors SSF. More broadly, the study also develops the first approach to addressing bias between stakeholders-by creating the General Factors (GF) group comprising factors to which stakeholders share delivery responsibility.   Figure 3a shows the strong agreement between the project parties in ranking the overall top 10 delay factors as summarized in Table 2. Noticeably, overall, employers and contractors are close in ranking the top 10 delay factors in PT projects. Moreover, the most critical five factors both overall and in view of the individual project parties from Table 3 are presented in Figure 3b, and support a close agreement in ranking the critical factors. While both overall and other project parties almost coincide, the consultants rank a few factors differently. Figure 3 underpins the claim of a less biased sample due to the introduction of the GF group.

Theoretical Contribution
Revisiting the updated literature review based on the study of Pall et al. (2016) [5], Figure 4 illustrates how this study contributes to advancing not just our understanding of delays in PT projects, but also our understanding of delays to power distribution, power generation, and non-power linear construction projects worldwide. With regard to PT projects, the study provides the first evidence of a unique group of delay factors SSF. More broadly, the study also develops the first approach to addressing bias between stakeholders-by creating the General Factors (GF) group comprising factors to which stakeholders share delivery responsibility.
projects, but also our understanding of delays to power distribution, power generation, and non-power linear construction projects worldwide. With regard to PT projects, the study provides the first evidence of a unique group of delay factors SSF. More broadly, the study also develops the first approach to addressing bias between stakeholders-by creating the General Factors (GF) group comprising factors to which stakeholders share delivery responsibility.

Practical Contribution
Delays are common for all types of projects, including power transmission (PT) projects, and these are widely recognized as a costly, complex, and risky problem [12]. Since delays are costly to all project parties, including extended timelines that threaten development, their minimization is important for all concerned. However, delays can be minimized when their causes are identified [126]. Building on the outcomes of this study, it is suggested that the project parties, including PT and other linear power and non-power project personnel, can significantly reduce delays by adopting the measures below: Owners to pay special attention to: • Finalizing the TL routes, paying special attention to legal issues and demographic information of the RoW in terms of community consultation, floods and soil properties; • funding the projects smoothly, with minimum official procedures and speedy approval of the project documents to maintain the seamless progress of site works; • establishing an effective communication protocol between the project parties, engaging an efficient project manager to identify priority areas to keep pace with the updated planned schedule;

Practical Contribution
Delays are common for all types of projects, including power transmission (PT) projects, and these are widely recognized as a costly, complex, and risky problem [12]. Since delays are costly to all project parties, including extended timelines that threaten development, their minimization is important for all concerned. However, delays can be minimized when their causes are identified [126]. Building on the outcomes of this study, it is suggested that the project parties, including PT and other linear power and non-power project personnel, can significantly reduce delays by adopting the measures below: Owners to pay special attention to:

•
Finalizing the TL routes, paying special attention to legal issues and demographic information of the RoW in terms of community consultation, floods and soil properties; • funding the projects smoothly, with minimum official procedures and speedy approval of the project documents to maintain the seamless progress of site works; • establishing an effective communication protocol between the project parties, engaging an efficient project manager to identify priority areas to keep pace with the updated planned schedule; • ensuring the engagement of technically sound and experienced contractors and consultants, considering their resources and capabilities in line with the project's scope; • exploring and maintaining an effective framework, obtaining the timely approval of the drawings and design; and • focusing on the activities and holding coordination meetings between TL and SS contractors, minimizing the risks of TL route changes.

Contractors to consider:
• Better understanding their legal and contractual obligations, involving finalizing a route with minimum RoW problems and least TL route changes; • establishing an efficient communication and coordination framework, ensuring timely interactions between the subcontractors, owners, and other project stakeholders; • ensuring the continuous flow of funds, reducing the dependency on payments from the owners; • engaging a dedicated and scope-wise team of experts, dealing with drawing design-related issues and timely monitoring progress; • updating the planning and scheduling of the project's progress, ensuring resource availability and taking into account natural calamities and political interventions; and • appointing locally experienced and technically sound staff, especially the project manager, providing quick solutions to problems that arise during the project life cycle.

Consultants to consider:
• Finalize the route, visiting the site physically, and considering the country-specific laws for the selection and compensation related to RoW; • engage a dedicated team with capabilities and expertise suited to a specific project; and • review the submitted design-drawings as soon as possible, discussing any issues to expedite approval.

Conclusions
The overall results provide strong evidence that the sector-specific factors (SSF) comprise the most critical group causing significant delays in PT projects, followed by general factors (GF) and external/unavoidable factors (E_UF). Collectively, the most critical factors are RoW problems, frequent changes in TL routes, accessibility of the tower locations, poor communication and coordination among the project parties, and payment delays. Furthermore, there is a strong agreement between the project parties, indicating that all the stakeholders are acutely aware of the critical factors involved.
The study provides insights into the causes of time overruns encountered in the implementation of PT projects. Most specifically, the findings allow professionals to develop more realistic project schedules and to include measures to mitigate delays and the corresponding financial losses associated with delays. For project management practitioners, the research also provides insights into the causes of delay in power distribution, power generation and non-power linear projects and provides a substantial foothold for advance study of the causes of PT project delay worldwide. Furthermore, since PT is an essential part of an electric power system, a key contribution of this paper is its potential for the advancement of future human civilization.
The study's limitations relate to the extent to which the analysis can speak to the subtle and nuanced ways the factors interrelate. Hence, further analysis using such techniques as structural equation modeling (SEM) and discrete choice analysis (DCA) are likely to yield a further understanding of the relationships between the factors involved. That said, and given the size and importance of the PT sector worldwide, the study provides desperately needed evidence and advice to significantly advance value for money in the delivery of power projects and, in turn, contribute to global economic growth. They are lack of owner's abilities and strategies to manage high-tech oriented mega project, frequent changes of routes, inappropriate project delivery system, lack of proper scheduling tool tailored for a linear mega project, redesign and change orders Highway/Road Projects 1 Amoatey, C.T. and A. Alfred Nii Okanta [44] Delay in finance and payment of completed work by owner, inadequate contractor experience, changes in scope by the owner during construction, delay to furnish and deliver the site to the contractor, inflexible funding allocation for project items 2 Soeng, S. and D.S. Santoso [45] Working during rainy season, awarding the project to the lowest bidder, impact on people's land along the road construction project, poor site arrangement, management and supervision, frequent equipment breakdowns, long distance to borrow pits, poor ground condition and terrain, low productivity of labor, inadequate modern equipment, late progress payments 3 Aziz, R.F. and A.A. Abdel-Hakam [46] Weather conditions, shortage (availability) in construction materials, slowness of the owner decision making process, poor site management and supervision by contractor, shortage of labor, accidents/mistakes during construction, slow delivery of materials, construction methods, shortage in equipment/insufficient numbers, financing by contractor during construction 4 Bruland, A., N. Dmaidi, and I. Mahamid [48] Political situation, segmentation of the west bank and limited movement between areas, award project to the lowest bid price, progress payment delay by owner, shortage of equipment 5 Kaliba, C., M. Muya, and K. Mumba [49] Delayed payments, financial processes and difficulties on the part of contractors and clients, contract modification, economic problems, materials procurement, changes in drawings, staffing problems, equipment unavailability, poor supervision, construction mistakes, poor coordination on site, changes in specifications, labor disputes and strikes 6 Mansfield, N.R., O.O. Ugwu, and T. Doran [50] Finance and payment arrangements, poor contract management, materials shortages, inaccurate estimating, overall price fluctuations 7 Meeampol, S. and S.O. Ogunlan [51] Construction method, management of construction resources, schedule management, supervision and control, communication 8 Aditya, A.K., D.A. Douglass, and M. Bhattacharya [47] Decision making, difficulties in execution, failure of the contractor to perform Other Projects 1 Sambasivan, M., et al. [95] Delay in progress payments, defective planning, delay in delivery of materials, unforeseen site condition, poor site management by contractors, consultant's late approval of tests and inspection, lack of communication between the project parties, delays in drawings approval 2 Mpofu, B., et al. [96] Unrealistic contract duration imposed by client, incomplete design at the time of tender, too many scope changes and change orders, inadequate planning and scheduling, poor project planning and control 3 Kumar, S. [97] Testing & qualification facility, raw material availability, design changes, hidden activities, lack of expertise, unexpected incidents, conflicts  Jalal, M.P. and S. Shoar [98] Labors rework, rework by consultant workforce, operation suspension, delay in progress payments, ineffective planning and scheduling of project, low productivity level of labors, change orders in documents, error in execution 5 Georgy, M., M. Kadry, and H. Osman [99] Delays in site possession, change orders, unexpected adverse weather conditions, unavailable or limited mobilization area, poor planning, lack of adequate project coordination, issues clearing customs, delay in material fabrication, obstruction to owner-controlled site access, theft 6 Famiyeh, S., et al. [100] Financial problems, unrealistic contract durations imposed by clients, poorly defined project scope, client-initiated variations, underestimation of project cost by consultants, poor inspection/supervision of projects by consultants, underestimation of project complexity by contractors, poor site management, inappropriate construction methods used by contractors, delays in the issuance of permits by government agencies 7 Oluwole, A. [101] Design and documentation issues, effectiveness of financial management approaches, project management and contract administration approaches, efficiency in human resource, efficiency of materials and plant resources, contractor's site management style, information and communication technology tools, external factors 8 Agyekum-Mensah, G. and A.D. Knight [102] Inadequate planning, finance and payment, slow in approving, variation, ground condition, labor supply and subcontractors, design changes, material shortage, manufactured and imported items, site management, weather, fluctuation, construction mistake, contractors experience, contingency or unforeseen 9 Adam, A., et al. [85] Lack of communication between contractors and clients, inefficient communication, delayed payment to contractors/consultants, poor financial planning, price increases 10 Samarghandi, H., et al. [86] Lack of attention to inflation and inefficient budgeting schedule, inaccurate budgeting and resource planning, weak cash flow and inaccurate pricing and bidding, inaccurate first draft and inaccuracies in technical documents, shortage of materials, price fluctuations 11 Abu Hassan, M.H.A. [87] Low productivity of labor, delay in decision making, changes to the project by owner, delays related to subcontractors' work, unqualified workforce 12 Rao, B.P., et al. [88] Delay in making the payments, lack of communication between parties, late issue of instruction, poor management and execution, delay in approving design document, 13 Arantes, A., P.F. da Silva, and L.M.D.F. Ferreira [89] Slow decision making, changes in work scopes, unrealistic scheduling, poor contract specifications, contractor's financial inability and inappropriate bidding and contract award process 14 Bagaya, O. and J. Song [90] Financial capability of the contractor, financial difficulties of the owner, equipment availability of the contractor, slow payments for completed work, poor sub-contractor performance by the contractor 15 Manzur, A., N. Ganesan, and M. Vinay [91] Complexity in structural design of project, revisions to drawing during construction stage, slow site clearance, frequent rains, inadequate equipment, unqualified/unskilled laborers, quarry strike 16 Lindhard, S.M., et al. [92] Unsettled or lack of project funding, delayed or long process times by other authorities, unsettled or lack of project planning, errors or omissions in construction work, lack of identification of needs 17 Kim, S.-Y., K.N. Tuan, and V.T. Luu [93] Financial difficulties to owner, lack of supervisor's responsibilities, change design by owner, incompetence contractor, inadequate contractor experience, delay in subcontractors' work, change function of hospital from owner, lack of consultant's experience, incompetence owner, obsolete equipment 18 Oyegoke, A.S. and N.A. Kiyumi [94] Selection of the lowest bid, instead of best bid for the client, financial condition of the main contractor, delay in decision-making by the client, poor construction planning by the main contractor 19 Shahhossein, V., M.R. Afshar, and O. Amiri [75] Lack of timely financial allocation, payment delays to the contractor, changes and/or additional works 20 Angelidi, A. [76] Change in orders by client during construction, slow decision making by client, insufficient and unclear information and details in design documents, lack of knowledge and experience of design team, poor coordination/communication between owner and design engineer during design phase 21 Lo, T.Y., I.W. Fung, and K.C. Tung [77] Inadequate resources due to contractor/lack of capital, unforeseen ground conditions, exceptionally low bids, inexperienced contractor, works in conflict with existing utilities, poor site management & supervision by consultant Lack of determination of entitled government, lack of incentive for private investment, no qualified bidder, improper contract planning, uncompleted client-finished items, fluctuation on resource price, construction schedule delay, unclear definition of compensable and non-compensable project items 23 Ahsan, K. and I. Gunawan [79] Lengthy procedure for contract evaluation and award, procurement delay, civil works and land acquisition delay, consultant recruitment delay, natural calamities, government procedural delay, local politics and economic problem, loan approval and disbursement delay, project staff hiring delay, new scope addition, frequent change of project staff (manager, director) 24 Marzouk, M.M. and T.I. El-Rasas [80] Delay in progress payments by owner, variation orders by owner during construction, effects of subsurface conditions, unskilled labors, defective planning and scheduling of project, contractor's financial inability, project bidding and award types (negotiation, lowest bidder), shortage of construction materials, late approval of design documents by owner, less productive workforce 25 Aziz, R.F. [81] Delay in progress payments (funding problems), different tactics patterns for bribes, shortage of equipment, ineffective project planning and scheduling, poor site management and supervision, poor financial control on site, rework due to errors, selecting inappropriate contractors, sudden failures actions, inadequate planning 26 Joseph, I.T.B., K.M. Augustine, and A.K. Theophilus [82] Time constraints, financial issues/changes in micro economic indicators, delayed payment problems, availability of resources, poor project management structures, lack of technologically based systems 27 Doloi, H., A. Sawhney, and K.C. Iyer [83] Delay in approval process, design and scope changes, change of subcontractors in the project, improper planning, inability of contractors to effective planning and controlling 28 Doloi, H., et al. [84] Lack of commitment, inefficient site management, poor site coordination, improper planning, lack of clarity in project scope, lack of communication, substandard contract 29 K Pai, S. [65] Too short contract duration, delay in progress payments, ineffective planning and scheduling of project by contractor, late in reviewing and approving design documents by consultant, mistakes and discrepancies in design documents, delay in material delivery, equipment breakdowns, shortage of labor, effects of subsurface conditions (e.g., soil, high water table) 30 Morris, S. [66] Poor project planning and management skills, inadequate technical skills, poorly done ground surveys in the case of mining projects, delays in construction and equipment supply by other public enterprises 31 Venkatesh, M.P., S.M. Renuka, and C. Umarani [67] Shortage of laborers, delivery of materials, shortage in construction materials, extra works (change orders and reworks), preparation of scheduling networks and revisions, skill of laborers, procurement of materials, materials selection and changes in types and specifications, maintenance of equipment, adverse weather effect on construction activities 32 Khoshgoftar, M., A.H.A. Bakar, and O. Osman [68] Finance and payments of completed work, improper planning, site management, contract management, lack of communication between the parties 33 Bekr, G.A. [69] Security measures, government change of regulations and bureaucracy, official and nonofficial holidays, low performance of lowest bidder contractors in the government tendering system, design and changes by owner, design changes by consultants, delay in progress payments by the owner, problems with local community, owner's lack of experience in construction 34 Mezher, T.M. and W. Tawil [70] Financing and the scheduling of subcontractors, contractual relationships, design changes by owners, project management, rated shop drawings Resettlement issues with political interference, non-availability of land with a higher cost of land transactions, weak planning institutions, rehabilitation issues with extensive legal delays 40 Skitmore, M. and A. Al-Kharashi [56] Inexperienced contractor's technical staff, contractor's poor site management and supervision, suspension of work by the owner, delayed approval of major changes in the scope of work by consultant, shortage of construction materials, shortage of manpower 41 Enshassi, A., J. Al-Najjar, and M. Kumaraswamy [57] Strikes and border closures, lack of materials in markets, delays in materials delivery to the site 42 Mohammed, K.A. and A.D. Isah [58] Improper planning, lack of communication, design errors, shortage of supply 43 Assaf, S.A. and S. Al-Hejji [59] Shortage of labor, unqualified workforce, inadequate contractor's experience, difficulties in financing project by contractor, low productivity level of labor, rework due to errors during construction, delay in progress payments by owner, original contract duration is too short 44 Mahamid, I., A. Al-Ghonamy, and M.
Aichouni [60] Bid award for lowest price, changes in material types and specifications during construction, contract management, duration of contract period, fluctuation of prices of materials, frequent changes in design, improper planning, inflationary pressure, lack of adequate manpower, long period between design and time of implementation, payments delay, poor labor productivity and rework 45 Yang, J.B. and S.F. Ou [61] Unforeseen site conditions, inadequate contractor skill, low-quality delay by poor materials 46 Toor, S.U.R. and S.
Ogunlana [62] Lack of resources, poor contractor management, shortage of labor, design delays, planning and scheduling deficiencies, changed orders, contractors' financial difficulties 47 Ulubeyli, S., N. Tuncbilekli, and A. Kazaz [63] Design and material changes, delay of payments, cash flow problems, contractor's financial problems, poor labor productivity, estimation problems, lack of feasibility studies, construction defects, unbalanced number of workers, fluctuation in material prices 48 Faridi, A.S. and S.M. El-Sayegh [64] preparation and approval of drawings, shortage of manpower, poor supervision and poor site management, productivity of manpower, skill of manpower, non-availability of materials on time, obtaining permit/approval from the municipality/different government authorities, financing by contractor during construction, inadequate early planning of the project, slowness of the owner's decision-making process 49 Alinaitwe, H., R. Apolot, and D. Tindiwensi [52] Changes to the scope of work, delayed payments, poor monitoring and control, the high cost of capital, political insecurity and instability 50 Aigbavboa, C.O., W.D. Thwala, and M.J. Mukuka [53] Delay in progress payments, difficulties in financing projects by the contractor, delay in approving major changes in the scope of work 51 Yang, J.-B. and P.-R. Wei [54] Changes in client's requirement, complicated administration process of client, insufficient or ill-integrated basic project data, unrealistic design duration imposed, slow land expropriation due to resistance from occupants Power Generation Projects 1 Batool, A. and F. Abbas [17] Lack of political will, delay in civil work, delayed release of government funds, poor law and order situation, improper site investigation, poor management of project schedule 2 Pillai, N.V. and K.P. Kannan [127] Improper technical project report, delay due to inter-state aspects, delayed authorization by central/state authorities, foreign currency exchange rates, land acquisition and rehabilitation, scope of work changes, changes in key personnel responsible for the advance planning and execution, erection specialists unavailability, construction materials shortage in market, spare parts of construction equipment, procurement delay of equipment, equipment delivery delay due to supplier's schedule failure and delay in delivering equipment at site Power Distribution Projects 1 Yau, N.-j. and J.-b. Yang [19] Improper technical project report, Delay in land acquisition and rehabilitation, defective review process of government agencies, over-subjective clarification of rules by government officer, unfinished land usage changes, inappropriate review on related regulations, errors in estimate, delay due to long for architectural permissions, other construction projects delay and political intervention