4.3. Confirmatory Factor Analysis (CFA)
The panel of domain experts within the Delphi survey were consulted to develop the hypothesised factor structure or latent constructs for the CFA. This was performed via three iterative rounds of structured feedback to identify, categorise, and validate the underlying dimensions of the 24 success factors associated with SAPH. These factors were labelled as “Risk Factors” as they represented the calculated risk impact of each factor (
Table 6). The resulting consensus was used to inform the priori groupings of observed variables into latent constructs. The groupings were as follows:
IBM SPSS Amos 31 (Analysis of Moments version 31) was used to execute the CFA to model the pattern of relationships among factors to reflect a common construct. At the model level of the analysis, the hypothesised model fit was assessed to investigate the level of correlation among observable factors within each latent construct [
109]. At the item-level analysis, the relationship between each variable and construct in standardised and unstandardised metrics, the level of covariance among constructs and the relationship between the error terms with respect to the observed indicators were estimated [
96]. Furthermore, at the scale-level analysis, the hypothesised factor model structure was estimated for confirmation given model fit indices and assessed [
110]. Maximum Likelihood Estimation (MLE) was employed to estimate the factor loadings by identifying the parameter values that maximise the likelihood of observing the given data. This is consistent with the assumptions and requirements for CFA [
109]. The CFA model that was estimated from hypothesised constructs is shown in
Figure 2.
The overall fit was measured by the chi-squared value, X
2 (156) = 196.105, and significance = 0.006, proving that the data is significant as
p > 0.05 [
111]. The relative chi-squared, X
2/df = 1.32, indicated an excellent model fit as X
2/df < 2 [
112], which suggests that the hypothesised measurement model adequately represents the observed data structure. The RMSEA = 0.045 was <0.05 [
113], which showed an acceptable fit per degree of freedom, and the PGFI = 0.694 was >0.5 [
114], which is a widely used threshold that shows a reasonable model parsimony using adjusted GFI. However, the CFI = 0.782 was <0.90 [
115], which shows a poor model fit as compared to a null model; the GFI = 0.885, which was <0.90 [
116], does not represent a good model fit; the RMR = 0.083, where lower values indicate a better measure for average residuals [
117] reflects a moderate model fit; the AGFI = 0.853 was <0.90 [
116], which indicates that there is not a good fit for model complexity using adjusted GFI; the NFI = 0.494 was significantly below the threshold for a good fit, which is 0.9 [
118]; the PNFI = 0.430 should be >0.5 [
114], so this result shows a low and poor model parsimony; the IFI = 0.802 was <0.9 [
111], which shows a poor sample size and model complexity fit; the RFI = 0.419 was significantly below the threshold > 0.9 [
111], which shows a very poor fit for adjusted NFI for degrees of freedom; and the AIC = 278.105 and the BIC = 403.149 were both relatively high values, whereas a good fit reflects low values [
119,
120]. These model fit indices generally depict a poor model which needed major revision for more compatible and correlated observable variables for latent constructs.
Furthermore, the majority of the factor loadings for each latent construct were weak, as the threshold for acceptable factor loadings is >0.5 [
121]. For the hypothesised latent construct, Policy, the loadings were 0.29, 0.30, 0.30, 0.32 and 0.27, respectively, which were all below the acceptable fit value of 0.5. Therefore, none of the observed variables belonged to this latent construct. For the second hypothesised latent construct, Stakeholder Involvement and Management, represented by “Stakeh”, also showed all loadings below the value of 0.5, which included 0.43, 0.33, 0.48, 0.47, and 0.43, respectively. For the third construct, Energy Consumption, represented by “Energy”, showed only one factor loading, RISK18, with a loading of 0.54, which is barely over the acceptable threshold of 0.5, followed by the other factor loadings of 0.49 and 0.33, which were both unacceptable. The final latent construct, Project Planning and Control represented by “Project”, also showed no factor loadings beyond 0.5, including 0.38, 0.37, 0.44, 0.27 and 0.30, respectively. The covariances among latent constructs also suggested overlapping constructs or misplaced items due to the many high inter-factor correlations that exceed 1.0, such as the Policy–Stakeholder Involvement and Management correlation of 1.10, the Policy–Project Planning and Control correlation of 1.13 and the Energy–Project Planning and Control correlation of 1.08. This suggests that these latent constructs are inherently interconnected in practice and underscores the systemic nature of SAPH delivery, where economic, governance, and technical dimensions cannot be entirely isolated.
This poor CFA model fit indicated that the hypothesised groupings of CSFs did not adequately represent the underlying data structure of SAPH in SIDS. This outcome suggests a divergence between theoretical assumptions for SIDS and international studies. This then justifies that construction and housing studies are highly context specific [
20]. Therefore, these initial CFA groupings may not fully capture the nuances of SAPH in the Caribbean SIDS context. This likely reflects the contextual limitations in the literature within the Caribbean SIDS. There may be a lack of education [
122], transparency [
123], systemised operations [
124], cultural differences [
61] and scepticism by practitioners [
67], among other factors, when implementing low-ranked factors within the Caribbean industry, although they are prominent in other nations. This reinforces the need for localised theory-building that reflects the complex systems interactions of SAPH in SIDS.
Due to these issues, an Exploratory Factor Analysis (EFA) was conducted to generate groups with stronger correlation for suggested latent constructs.
4.4. Exploratory Factor Analysis (EFA)
Since the hypothesised factor model demonstrated several empirical concerns, suggesting that latent constructs developed by the Delphi technique contradict the statistical consistencies among observable factors from respondents, a post hoc EFA was conducted. The purpose was to empirically reassess the dimensional structure of the data without imposing prior assumptions. This allowed for the identification of potentially more valid and statistically coherent factor groupings via statistical analysis based on common variance [
122].
EFA was used to extract the minimum number of variables with the highest portion of variance and give statistical guidelines for accurate allocation of observable factors. The Principal Component Analysis (PCA) extraction technique was used, as it summarises most of the variance into a minimum number of factors. The Promax rotated factor solution, an oblique rotation method, was employed for maximisation of each variable on a single latent construct to assume that each latent construct allowed the correlation of factors, as there may be underlying dimensions among the latent constructs given the complex and social intricacies of SAPH.
The total variance explained output from the EFA employing the PCA technique and Promax rotation revealed five components that explain 44.31% of the total variance before rotation as shown in
Table 7. The rotated output redistributed variance more evenly, with the first five components contributing 2.548, 2.216, 2.028, 1.724, and 1.493 in terms of eigenvalues, respectively. The higher the eigenvalue over the threshold of 1, the more meaningful the category or construct. These 5 factors represent 5 underlying dimensions or constructs that summarise the 20 observed variables used as the independent components of this research. The Scree Plot, shown in
Figure 3, is an output of IBM SPSS Statistics version 31 which shows a graph of eigenvalue versus component number. The blue dots represent the eigenvalue of each extracted component to indicate the proportion of variance in the dataset explained by that component. The black line connects these eigenvalues to highlight the overall trend of decline as successive components account for progressively smaller amounts of variance. The key point of interpretation lies in the “elbow” of the plot which is highly objective and should align with the Total Variance for EFA values (
Table 7). The point at which the optimal number of components should be retained is indicated where the sharp initial decline transitions into a more gradual slope. This plot shows that the graph gradually plateaus after the fifth component as additional components beyond this point contribute minimally to explaining the variance. This then confirmed the retention of five components based on the Kaiser criterion of eigenvalues > 1, which shows that there are 5 latent constructs that can be assembled within this analysis.
The Pattern Matrix (
Table 8) shows the structure of variables for each suggested construct after Promax rotation and allows correlation among components. Many strong loadings (>0.4) are noted, which show high correlation and consistency among factors within each component. RISK10 was the only factor with a loading of <0.3 and was therefore omitted from the revised SEM construct groupings. Furthermore, RISK7 was excluded due to poor communalities and excessive loading onto a unique factor (0.996) during consistency checks. RISK7 was also ranked the lowest or least important CSF when the algebraic mean was calculated and shown in
Table 5. These metrics suggested it was an outlier with little significance and was therefore omitted from the SEM.
The restructuring of the latent constructs using the EFA was primarily driven to enhance the statistical coherence and contextual realism of the underlying data structure. This approach addresses the disparity between international literature versus context-specific construction and housing information within SIDS, where there is a significant research gap. Therefore, the revised groupings emerged organically from the data and revealed constructs that better reflect how practitioners in SIDS perceive and prioritise success factors in practice. This data refinement also enhances the robustness of the subsequent SEM analysis and provides a pragmatic foundation for future studies in construction and housing based on statistical validity and real-world practitioner insights within SIDS.
Therefore, based on the Pattern Matrix, the elimination of weak factors, and validation through expert panel review using the Delphi technique, the revised latent constructs were derived and are presented in
Table 9.
4.5. Structural Equation Model (SEM)
An SEM was conducted which performs both CFA and multiple linear regression (MLR) using the latent constructs (independent variables) with their corresponding observable variables and endogenous latent variable, in this case SAPH, to estimate the relationship between both components. This would reveal the constructs and success factors that influence SAPH most critically. The revised table of observable variables and latent constructs was used to perform the SEM along with the endogenous construct of SAPH. These factors were represented by RISK 8, 9 and 11.
Figure 4 depicts the SEM format of the relationship between CSF categories (latent constructs) and SAPH (endogenous variable), where “ConstrExec” represents Construction Execution, “EnergyEff_Transp” represents Energy Efficiency and Transparency and “Economic” represents Economic.
The model fit is accepted once one or more fitness requirements among the absolute fit, incremental fit and parsimonious fit are met [
109]. Within the absolute fit category, the chi-squared index X
2 = 196.105 indicated an acceptable fit, as it fell within the threshold of non-significance (
p < 0.05) [
125], as PClose = 0.668. The RMSEA = 0.045 was also accepted, as it does not exceed the threshold of 0.08 [
125] and suggests a good root mean square error of approximation fit. Within the incremental fit category, the indices examined included CFI = 0.91 and TLI = 0.90, which met the threshold of 0.9 [
125] and therefore suggested a moderate model fit. The parsimonious fit indices included X
2/df = 1.316, which falls within the acceptable range of 0–2 [
126]. Since at least one index per fitness category was accepted, this model is determined to be adequately fit. The model fit indices for this SEM are tabulated below (
Table 10) with a comparison table of threshold ranges and their interpretation (
Table 11) [
127].
The standardised regression weights table shown in
Table 12 depicts the estimates of the relationships between the latent constructs Construction Execution (ConstrExec), Energy Efficiency and Transparency (EnergyEff_Transp) and Economy (Economy) and the dependent variable, SAPH, as well as the relationships among each latent construct’s observed indicators. The construct with the strongest relationship with SAPH was the Economy factor (0.962), which reveals that economic factors are critical and directly impact SAPH. The second strongest relationship was between SAPH and Energy Efficiency and Transparency (0.767), which also shows a critical influence of these construct’s risk factors on SAPH. Finally, Construction Execution had a moderately positive but the least strong relationship with SAPH, where an increase of 1 standard deviation results in an estimated 0.396 standard deviation increase in SAPH.
Furthermore, the model reveals that the observed variables have strong loadings to their corresponding latent construct. This confirms that each construct accurately represents its group of observed variables. For the Economic construct, RISK23 (0.454) is the strongest indicator, followed by RISK6 (0.423) and RISK5 (0.374). From Energy Efficiency and Transparency, the strongest contributors were RISK12 (0.558), RISK18 (0.473) and RISK17 (0.463), and from the Construction Execution construct, the most critical factors included RISK15 (0.628), RISK16 (0.495) and RISK22 (0.454). These critical factors are summarised in the table below, starting with the strongest construct to the weakest construct and its most critical observable variables. These results are summarised in
Table 13.
Among the observed variables, the most CSFs within the Economic, Energy Efficiency and Transparency, and Construction Execution constructs, respectively, emerged as (i) risk reduction integration into the planning stage of the project life cycle, (ii) participation and commitment by government, public and private sectors and (iii) investment of key sectors and stimulation of urban economy. These risks demonstrated the strongest standardised regression weights and therefore contribute most critically to explaining the variance in SAPH.
The top CSF under the Economy category was risk reduction integration into the planning stage of the project life cycle as it relates to SAPH in SIDS. Economy was also proved to be the most critical category towards SAPH, as investment into the economic development of SIDS has the most critical impact towards achieving sustainable development, especially in SIDS [
128]. Risk reduction is deemed a safety principle whose foundations are built on intertwined environmental and societal systems. This shows that professionals understand that given the complexity, irreversibility, nonlinearity, and inherent uncertainty of these systems, it is increasingly more effective to focus on prevention rather than attempting to remedy the damage after it occurs [
129]. Safety and precautionary measures directly correlate to a reduction in the effect and consequences of the risk of failure [
130]. Risk reduction integration contributes to economic, social and environmental sustainability [
8], as disasters destroy property, livelihoods and the environment, increase morbidity [
1] and induce additional costs associated with loss of infrastructure and natural resources [
36]. The installation of risk reduction within the project life cycle should be considered from various interests and perspectives of every stakeholder involved in the project [
58].
As this relates to SIDS, risk reduction integration into projects should illustrate possible challenges that disasters and ever-prevalent matters such as climate change can pose for Caribbean countries, particularly those with relatively low elevations of cities [
48]. SIDS contribute less than 1% of greenhouse emissions globally [
24], yet due to their dependent and volatile economy, size, location and geography, they are some of the most vulnerable nations to climate change when compared to the rest of the world. The threat of climate change to an already susceptible country can mean greater risks of droughts, flooding, tsunamis and other environmental hazards [
1]. This then institutes the urgency of risk reduction integration into the planning of projects [
108,
131]. Risk reduction measures such as mainstreaming of hurricane-resilient and building-resilient construction standards, stronger disaster management of communities and upgraded early-warning signals should all be implemented and improved on by all governments and institutions [
41]. The high ranking of risk reduction integration highlights its pivotal role in achieving SAPH in SIDS. These results show that respondents understand that risk reduction can serve the alleviation or prevention of large-scale disaster risks associated with climate change and other safety hazards.
The most influential CSF within the Energy Efficiency and Transparency grouping was participation and commitment by government, public and private sectors. In many developing countries, especially Caribbean SIDS, there is a lack of access to resources and technologies to aid in advancing and sustaining essential infrastructure and construction. Here, partnerships drive innovation. The private sector can often offer these resources and become involved in public–private partnerships (PPPs) under privatisation for the benefit of the country’s economic development [
132]. Partnership between the government and the private sector also improves its ability to protect and restore local infrastructure and natural resources through green projects, incentives and risk-sharing mechanisms [
133]. The need for improved and sustainable infrastructure, such as SAPH, is proliferated due to the onset of climate change and urbanisation [
1]. This has introduced the concept of Green PPPs as a catalyst for green and sustainable infrastructure. Green PPPs increase progress in renewable energy, sustainable urban mobility, water management, waste management, green building and urban greening [
134]. Therefore, participation of the private sector within public projects for sustainable development such as SAPH is critical for its successful implementation and adoption in SIDS. Although several barriers to PPPs are to be addressed, such as lack of cost reduction methods and cost overruns, lack of modern and innovative approaches by contractors for projects and political interference, bias and nepotism [
132]. In SAPH, transparent approaches that account for maintaining positive and sustainable PPP investments are mandatory for the public and energy efficiency (EE) initiatives.
The second most influential CSF within this category was the implementation of renewable energies towards achieving SAPH. Nonrenewable energies such as coal, oil and natural gas are used to power buildings, water and wastewater systems, transportation and other essential activities for daily life in excessive amounts, resulting in depleted energy resources and heavy pollution. This has raised concern for sustainable energy use of energy through renewable sources that have natural derivatives, such as solar, wind, biomass, hydropower and geothermal sources, to power buildings, especially housing [
135]. Sustainable buildings usually acquire energy from onsite or nearby energy-converting systems such as solar roofs, photovoltaic (PV) technology, solar thermal or green roofs, where energy is also saved in batteries for continuous usage when natural resources, such as sunlight, are fluctuating [
47]. In SIDS, many countries are challenged due to energy and land scarcity given the relatively small land area and access to natural resources, and recyclable resources such as waste-to-energy are suggested [
136].
The most crucial success factor within the Construction Execution category was investment in key sectors and stimulation of the urban economy. This refers to the strategic allocation of resources to sectors relevant to SAPH, such as construction, infrastructure, transportation, energy, etc., and increased urban development, such as activities towards a burgeoning economy, employment opportunities and sustainable social growth and community [
10]. Sustainable urban development has become a challenge within the past decades due to the rate of urbanisation and population growth, albeit socioeconomic and environmental issues, whereby by 2050, the urban share of the population is estimated to be 70% [
43]. In SIDS, countries can reach 100% population concentration in urban areas such as Anguilla, the Cayman Islands, Guadeloupe and Singapore due to demographic growth and increased industrialisation [
136]. Urban development and economy refer to economic input into sustainable development cities where there is a balance of environmental, social, economic and institutional factors and work towards achieving SDG 11, “Make cities and human settlements inclusive, safe, resilient, and sustainable” [
107]. Investment should be allocated to support the long-term development of the community, such as the environment, economic activity, health, education, employment and quality of life [
8]. Some barriers to this include political interference, the investment climate on a global scale, interstate relations and the global economic fluctuations that affect SIDS disproportionately [
128]. However, investment into key sectors that support SAPH and sustainable urban development are critical for the success of construction execution towards SAPH.
Another CSF of SAPH within Construction Execution was revealed to be training and education for all sectors on sustainable practices, energy conservation and the importance of sustainability. Literacy and training in sustainability are fundamental success factors in the attainment of SAPH, as persons must first understand the importance and value in utilising sustainable materials if they are to meet the conservation of resources for generations of the future [
44]. In order to mainstream sustainable practices, the general public, all sectors of the construction industry and all government bodies must be sensitised [
20]. This CSF was ranked second within Trinidad and Tobago, as respondents have acknowledged and unanimously agreed that the need for education, training and public awareness regarding sustainability is crucial to the attainment of SAPH.
Moreover, these CSFs also contribute to the achievement of UN SDGs that are significantly associated with SAPH, including SDGs 1, 9 and 11. Risk reduction and preparation (0.454) is a preventive measure to prepare for disasters that occur within the Caribbean, especially due to the onset of climate change and SIDS’ disproportional vulnerability towards its detrimental effects [
1]. This contributes towards the targets of creating resilient cities described by SDG 11. The introduction of legalisation and consequences, such as taxes, on the use of unsustainable construction material and practices (0.423) also contributes to SDG 11, where a target is to reduce the dense emission of carbon into the atmosphere due to buildings and construction [
64]. The participation of the government and private sector (0.558) to achieve affordable housing aids in achieving SDG 1, where fiscal finances are used to end poverty by allowing the basic right to housing and amenities for the most vulnerable in society [
65]. The implementation of renewable energy (0.473) contributes towards SDG 9, which ensures the use of innovative technologies towards information, communication and transportation development [
54]. Furthermore, SDG 9 and SDG 11 are also achieved by the investment of key sectors and stimulation of urban economy (0.628). The industry becomes more developed and contributes towards sustainable growth and stimulation of the urban economy. This reduces the prevalence of urban sprawl and proliferates safe and healthy residential areas for residents of any socioeconomic background [
7].