Investigation of Wasteful Activities Using Lean Methodology: In Perspective of Kazakhstan’s Construction Industry

Like many other countries, the presence of wasteful activities is very common in Kazakhstan’s construction industry. This severely affects the productivity of construction processes. Lean methodology maximizes the value of a process by minimizing wasteful or non-value adding (NVA) activities. This study aims to explore and quantify the impact NVA items on construction productivity. Several observations were made for construction processes in Astana, Kazakhstan to investigate and quantify various types of wasteful activities. Moreover, a survey was conducted to examine the general understanding of wasteful activities and Lean methods within the construction industry in Kazakhstan. In terms of wasteful activities, a similarity was found between the observed construction processes and survey results. Furthermore, apart from the commonly found seven types of wasteful activities, some other sources of waste, such as “preparation” and “break”, were found from the observations. Finally, wasteful activities were mapped with commonly used Lean tools, as found in the literature, so that productivity can be improved by minimizing NVA activities. From the mapping and the survey results, value stream mapping (VSM) was found to be the most effective Lean tool, since it facilitates increased visualization.


Introduction
The construction industry in Kazakhstan accounts for 6% of country's GDP and the annual spending on all construction work was increased from KZT 2667 billion to KZT 3258 billion ($7.4 to $9.05 billion) in the years of 2012-2016. Despite the huge economic contribution, construction projects in Kazakhstan, like many other countries, face challenges related to productivity, quality of work, lack of effective management, low competitiveness of construction companies, insufficient volumes of high-level output, etc. [1,2]. This is because construction projects are characterized by the complex correlation and coordination of different functions and a large number of people are involved in a project [3,4], which eventually delays different construction operations, leading to cost and time overruns.
Considering the importance of the industry, the president of Kazakhstan identified the construction industry among the main priorities for economic development and instructed launching new breakthrough projects with improved performance. The concept of performance improvement deals with maximizing product value and reducing non-value adding activities in the construction processes [5,6]. This concept is in line with Lean thinking that focuses on delivering product with maximum quality, minimum resources, and reduced time.

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Questions about the participant's experience and roles in the project; • Questions regarding knowledge of Lean methods; • Questions regarding waste/non-value adding activities in construction process; and • Questions regarding Lean tools.
The questionnaire was set in the form of multiple-choice questions, which consisted of several answers so that the participant could easily choose the most appropriate option (the detail of the questionnaire can be seen in Appendix A). Such types of questions save the participants' time. The questionnaire was created with the help of the website www.freeonlinesurveys.com and the link was sent to people working in the construction industry through instant messengers and e-mail. A total of 123 construction professionals received the questionnaire.

Results and Analysis
Among the five observed construction processes, three sets of sample data are shown in Tables 1-3 for two construction processes "installation of a floor slab" and "cutting tile". The process "installation of floor slab" involved 3 persons, 1 crane operator and 2 installation workers. Table 1 shows the timing of the details of work for the crane operator. Table 2 depicts the timing for both the installation workers by classifying them as value adding (VA), non-value adding (NVA) and essential non-value adding (ENVA) activities. As defined in [31,33], VA contributes to the transformation of a product or service to the end result, done right from the first try and the customer is willing to pay for it. Whereas, ENVA is supporting activities that promote to the execution of value-adding activities, but do not add value. Finally, NVA uses resources but does not create value.
By comparing the data of Tables 1 and 2, it can be seen that when the crane operator was working (VA or ENVA) both the installation workers were waiting for their turns to come (NVA) and vice versa. Therefore, a significant amount of time was NVA time, as can be seen in Figure 1, which shows percentage of VA, NVA, and ENVA for all three people. More than half of the time for each person contributed to NVA activities. This is because each of the workers was waiting for other co-workers throughout the construction process, as evident from Tables 1 and 2. This is a typical characteristic when a construction process involves multiple workers.
Apart from waiting, other types of NVA activities were observed in different construction processes, such as "searching for tools", "walking to bring bracket/block/tools", "cleaning/screwing /unscrewing handrail fitting", "painting for second time", and so on. Moreover, each of the construction process consisted of several ENVA activities that used a significant amount of time in that construction process. For example, Table 3 shows timings of details of work for the construction process "cutting tile" by categorizing VA, NVA, and ENVA. In this case, one-quarter of the time was spent on NVA activities (see Figure 2). This value is much lower than the earlier case since one worker was doing the work and, hence, not dependent on other co-workers. However, 36% ENVA activities were engaged in the construction process. Table 1. Average data gathered from the VSM of the process "installation of a floor slab" for person 1 (crane operator).

No.
Detail of Work Classification Duration (s) % Of Total Time 1 Lowering the crane boom VA 22.5 15 2 Waiting while person 2 was walking NVA 6 4 3 Waiting while person 2 and 3 were fixing the slab to slings NVA 17 11 4 Lifting the crane boom ENVA 14.5 10 5 Turning the crane boom ENVA 16 11 6 Lowering the crane boom closer to the installation site ENVA 10 7 7 Waiting while person 2 and 3 were laying the mortar NVA 26 17 8 Waiting while person 2 and 3 were walking NVA 17 11 9 Lowering the crane boom to the installation site VA 6 4 10 Waiting while person 2 and 3 were positioning the slab NVA 10 7

11
Waiting while person 2 and 3 were installing the floor slab NVA 5 3 Total 150 100 Table 2. Average data gathered from the VSM of the process "installation of a floor slab" for person 2 (installation worker). Installation of the floor slab VA 5 3

No. Detail of Work
Total 150 100 Table 3. Average data gathered from the VSM of the process "cutting tile".  Apart from waiting, other types of NVA activities were observed in different construction processes, such as "searching for tools", "walking to bring bracket/block/tools", "cleaning/screwing /unscrewing handrail fitting", "painting for second time", and so on. Moreover, each of the construction process consisted of several ENVA activities that used a significant amount of time in that construction process. For example, Table 3 shows timings of details of work for the construction process "cutting tile" by categorizing VA, NVA, and ENVA. In this case, one-quarter of the time was spent on NVA activities (see Figure 2). This value is much lower than the earlier case since one worker was doing the work and, hence, not dependent on other co-workers. However, 36% ENVA activities were engaged in the construction process. Table 3. Average data gathered from the VSM of the process "cutting tile".

No.
Detail of Work Classification Duration (s) % Of Total Time 1 Searching for tools (pen and measuring tape) NVA 5 2 2 Measuring the required size ENVA 14 6 3 Marking the required size ENVA 18 7 4 Cutting the required size VA 57 22 5 Marking of openings ENVA 15 6 6 Cutting of openings  VA  47  19  7  Grinding  ENVA  20  8  8  Transportation of tile  NVA  26  10  9  Discussion of work  ENVA  24  9  10 Unnecessary taking, waiting, and smoking NVA 28 11 Total 254 100 Figure 2. Summary of the VSM data of the process "cutting tile".
Similar classifications were made for three other construction processes and the percentages of VA, NVA, and ENVA activities are shown in  A varying amount of NVA and ENVA were observed in these processes as well. Afterwards, a summary was made from Figures 1-5 by averaging the percentages of time for VA, NVA, and ENVA activities for all of the five observed construction processes. Figure 6 shows the average timing, in terms of percentage, for each type of activity. As can be seen in Figure 6, only 33% of the workers' time was spent on value adding activities. Nearly 41% of time was consumed in execution of essential non-value adding activities, which needed to be reduced. Additionally, about 26% of time was non-value adding activities, which should be eliminated.  Figure 6 shows the average timing, in terms of percentage, for each type of activity. As can be seen in Figure 6, only 33% of the workers' time was spent on value adding activities. Nearly 41% of time was consumed in execution of essential non-value adding activities, which needed to be reduced. Additionally, about 26% of time was non-value adding activities, which should be eliminated.
Some variations can be found in the percentages of VA, NVA, and ENVA when comparing the results from observations made in Astana with those available in literature. For instance, a study conducted by Jens and Kristensson [34] found 44% VA activities in construction process, while the percentages of NVA and ENVA accounted for 36% and 20%, respectively. On the other hand, Mossman [35] assessed that the volume of NVA activities were in the range of 55%-65%. VA accounted for only 5%-10%, while the remaining 30%-35% were ENVA activities. Comparing the observed results in Astana and the conducted survey results, similarities can be noticed.

Survey Results
The survey questionnaire was sent to 123 construction professionals. The survey received 28 responses with a 23% response rate. It can be seen from the responses received that all the participants were familiar with Lean methodology. This indicated that persons who were aware of Lean methodology participated in the survey. This was also indicated by a low response rate. Therefore, it was not possible to categorized responses based on the respondents' familiarity with Lean methodology. Figure 7 shows the distribution of the work departments of the respondents, which shows that a wide range of construction professionals, including managing directors, project managers, heads of construction sites, site engineers, surveyors, foremen, and others, answered the survey questions. The majority of the participants were involved in the field of construction and were aware of wasteful activities in the construction process. Moreover, the working experiences of most of the participants were found to be from 1 year to more than 10 years. Therefore, the obtained survey results can be considered as representative.
conducted by Jens and Kristensson [34] found 44% VA activities in construction process, while the percentages of NVA and ENVA accounted for 36% and 20%, respectively. On the other hand, Mossman [35] assessed that the volume of NVA activities were in the range of 55%-65%. VA accounted for only 5%-10%, while the remaining 30%-35% were ENVA activities. Comparing the observed results in Astana and the conducted survey results, similarities can be noticed.

Survey Results
The survey questionnaire was sent to 123 construction professionals. The survey received 28 responses with a 23% response rate. It can be seen from the responses received that all the participants were familiar with Lean methodology. This indicated that persons who were aware of Lean methodology participated in the survey. This was also indicated by a low response rate. Therefore, it was not possible to categorized responses based on the respondents' familiarity with Lean methodology. Figure 7 shows the distribution of the work departments of the respondents, which shows that a wide range of construction professionals, including managing directors, project managers, heads of construction sites, site engineers, surveyors, foremen, and others, answered the survey questions. The majority of the participants were involved in the field of construction and were aware of wasteful activities in the construction process. Moreover, the working experiences of most of the participants were found to be from 1 year to more than 10 years. Therefore, the obtained survey results can be considered as representative. In response to the question about effectiveness of the Lean methodology, 82% of the respondents agreed that Lean method is effective or very effective in improving construction operation, while the remaining respondents indicated that it has little effect in reducing wasteful activities (see Figure 8). While one can argue about the effectiveness of the Lean method to improve construction processes in Kazakhstan, the survey results indicate that the construction professionals have a positive attitude about the usefulness of Lean methodology.  In response to the question about effectiveness of the Lean methodology, 82% of the respondents agreed that Lean method is effective or very effective in improving construction operation, while the remaining respondents indicated that it has little effect in reducing wasteful activities (see Figure 8). While one can argue about the effectiveness of the Lean method to improve construction processes in Kazakhstan, the survey results indicate that the construction professionals have a positive attitude about the usefulness of Lean methodology.

Managing
Regarding the percentage of non-value adding activities within a construction operation, a significant number of participants (about 57%) indicated that there are 10%-30% wasteful activities in the construction process (see Figure 9), which is very close to the observed results in actual construction sites.
The next question on the survey was about the types of wasteful activities that are common within the construction operation. In this case, the participants were asked to choose from the seven types of wasteful activities (without considering their frequency of occurrence) as they observed in their construction projects. As can be seen in Figure 10, 75% of the participants indicated defects or correction waste as the most frequent, followed by waiting time, motion waste, transportation waste, and others. Regarding the percentage of non-value adding activities within a construction operation, a significant number of participants (about 57%) indicated that there are 10%-30% wasteful activities in the construction process (see Figure 9), which is very close to the observed results in actual construction sites. The next question on the survey was about the types of wasteful activities that are common within the construction operation. In this case, the participants were asked to choose from the seven types of wasteful activities (without considering their frequency of occurrence) as they observed in their construction projects. As can be seen in Figure 10, 75% of the participants indicated defects or correction waste as the most frequent, followed by waiting time, motion waste, transportation waste, and others.  Regarding the percentage of non-value adding activities within a construction operation, a significant number of participants (about 57%) indicated that there are 10%-30% wasteful activities in the construction process (see Figure 9), which is very close to the observed results in actual construction sites. The next question on the survey was about the types of wasteful activities that are common within the construction operation. In this case, the participants were asked to choose from the seven types of wasteful activities (without considering their frequency of occurrence) as they observed in their construction projects. As can be seen in Figure 10, 75% of the participants indicated defects or correction waste as the most frequent, followed by waiting time, motion waste, transportation waste, and others.  In the next part of the survey, the participants were asked to rate each of the wasteful activities in terms of their frequency of occurrence in a five-degree Likert scale (never, rarely, occasionally, frequently, and very frequently). From the responses, the types of wasteful activities were ranked 0% 20% 40% 60% 80% Figure 10. Percentage of responses regarding the most common type of waste which can be found in construction. In the next part of the survey, the participants were asked to rate each of the wasteful activities in terms of their frequency of occurrence in a five-degree Likert scale (never, rarely, occasionally, frequently, and very frequently). From the responses, the types of wasteful activities were ranked based on the Relative Importance Index (RII), as can be seen in Table 4. The table depicts that 'waiting' was the most frequently occurred wasteful activity followed by 'defect', 'motion', 'transportation', and so on. A survey conducted by Ismail and Yosuf [36], in the Malaysian construction industry, also found that defects and waiting time were the major contributors to NVA activities. The wasteful activities, as found from the observations of the five construction processes, portray a similar trend to the survey results. According to the observations, 'waiting' and 'motion' were among the most frequent wasteful activities, followed by 'transportation', 'inventory', and 'over-processing'. However, 'defects' and 'overproduction' were not found in any of the five observations. The observed wasteful activities, which were identified as NVA activities, were categorized according to the types of waste and are presented in Table 5. As can be seen, waiting was observed in terms of waiting for other co-workers when a person was performing his/her work. On the other hand, motion waste was also observed as the prevailing type. A great amount of time was spent as motion waste while workers were searching for tools and materials. In most cases, the materials were stored in one place while the work was performed in another place and the workers were not sure about the type and/or the amount of material/tool needed for their work.
Another wasteful activity was found to be transportation waste. It was observed during the process of cutting a tile. Although the transportation waste was ranked 4th according to the survey result (see Table 4), in order to fully observe transportation waste it is necessary to focus on the external flow at construction sites, such as local material suppliers, poor job planning, inaccurate logs on vehicles and equipment, and so on.
The next type of waste identified from the observations was improper inventory. During the observations of construction sites, it was found that a lot of material and many tools were stored in one place from where workers spent some time to find his/her required tools or material. The results of the survey showed that participants noted this type of waste as not so common, but encountered nevertheless.
Over-processing waste occurred when the worker was painting the wall a second time. This activity does not match with the concepts of VA or ENVA activities. Although the work was done right the first time (in this case painting), it was the worker's intention to paint it for the second time.
Two types of waste, which were not observed in the five construction processes, were defects and overproduction waste, as mentioned earlier. The waste in the form of defect occurs when actions are needed to repair or redo the accomplished work. Among the five construction processes, there was no such case where an activity was performed incorrectly the first time, nor there was a need for additional work. On the other hand, overproduction waste is about producing more than it is required or demanded. Nevertheless, during this research investigation, there was no such case recorded and none of the investigated processes included work that could be overproduced. Waiting while person 2 was walking Waiting while person 2 and 3 were fixing the slab to slings Waiting while person 2 and 3 were laying the mortar Waiting while person 2 and 3 were walking Waiting while person 2 and 3 were positioning the slab Waiting while person 2 and 3 were installing the floor slab Waiting while person 1 was lowering the crane boom Waiting while person 1 was turning the crane boom Waiting while person 1 was lowering the crane boom closer to the installation site Waiting while person 1 was lowering the crane boom to the installation site Apart from the seven types of wasteful activities, as found in the literature, other non-value adding activities were identified during the observations. For example, the activities of "unnecessary talking, waiting, and smoking" can be categorized as "break waste". Moreover, there were other activities like "screwing/unscrewing handrail fitting" or "cleaning handrail fitting" which did not add value to the final product. These activities do not fall into the seven types of defined wasteful activities. Accordingly, such NVA activities can be classified as "preparation" waste. A study conducted by Arleroth and Kristensson [34] also identified similar waste categories by observing construction processes in Sweden.
To minimize the wasteful or non-value adding activities in the construction processes, Lean tools such as value stream mapping (VSM), increased visualization, 5S (Sort, Set in order, Shine, Standardize, and Sustain), and the Last Planner System are well known in the literature. These tools are mapped with the different types of observed wasteful activities and are presented in Table 6. The table shows a summary of observed types of NVA activities that can be improved with different Lean tools.

Motion Transportation Inventory Over-Processing Waiting Preparation Breaks
Value Stream Mapping The survey respondents also showed positive attitudes regarding the effectiveness of these Lean tools. The last question of the survey was to evaluate the effectiveness of the abovementioned four commonly used Lean tools. Table 7 shows the ranking of the tools based on RII. As evident from the RII values, all the tools were found to be effective, though the tool 5S was ranked the 1st. However, by comparing Tables 6 and 7, out of these 4 tools, the VSM technique can be identified as the most prominent considering its ability to improve different types of wasteful activities and the survey ranking. Moreover, the VSM tool is found to be very useful for the examination of processes, identifying wasteful activities, and distinguishing them NVA and ENVA. After identifying each type of waste, it is possible to take further actions to eliminate/minimize unnecessary steps, create flow, and ensure the continuous improvement of the construction process.

Conclusions and Discussion
Construction projects are characterized by low productivity that involves numerous wasteful activities in the construction processes. This study explored wasteful activities by means of Lean methods to improve productivity for construction projects in Astana, Kazakhstan. The method involved identifying and eliminating non-value adding activities in the construction processes. Several observations were made for some selected construction processes in Astana in order to categorize VA, NVA, and ENVA activities within a construction process and the percent of time for each activity type was quantified. It was found from the observations that the percentage of value-added activities contributed only 33%, while NVA together with ENVA activities occupied 67% of the total process time. Particularly, 26% of time spent on various activities were found to be pure waste, which came in the form of waiting, motion, transportation, inventory, over-processing, etc. Literature suggests that the time spent on ENVA activities should be minimized and that NVA activities should be eliminated. This minimization and/or elimination would eventually improve construction productivity.
A survey was also conducted as a qualitative assessment and to portray the perception of the construction professionals about Lean methods in Astana. Most of the survey participants indicated the presence of wasteful activities in the construction processes to be between 10%-30%, while the literature revealed the percentage of non-value adding activities to be between 36%-65%. Moreover, the frequency of different types of wasteful activities associated with construction processes showed a similar trend between the observed and survey results, where waiting and motion types of waste were found to be more frequent. In addition, apart from the seven types of NVA activities, as reported in the literature, other types of wasteful activities were found in the observed construction processes, which were categorized as "preparation" and "break" wastes.
This study provided a comprehensive understanding of Lean methodology for identifying and eliminating wasteful activities, so that productivity can be improved for the construction projects in Kazakhstan. Construction companies in Kazakhstan and other countries in the world can use the findings of this study to implement Lean method in their projects. Further investigations should be carried out to quantify the time and cost savings if the Lean method is used to improve construction productivity. Moreover, the company should carefully consider the necessary cultural changes within the organization to adopt the Lean project management approach for their projects. Funding: This research was funded by the Nazarbayev University Research Fund, grant number #SOE2017003 and "The APC was funded this grant". The authors are grateful for this support. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Nazarbayev University.

Acknowledgments:
The authors are grateful to the anonymous construction companies in Astana for the opportunity to conduct observations for this research work as well as the survey participants.

Conflicts of Interest:
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.