Development of a system model for cost management in low-cost housing projects in Nigeria

Poor project cost performance is one of the vital issues challenging successful construction project delivery particularly in developing countries such as Nigeria. This issue is endemic particularly in Low-cost housing (LcH) projects with adverse effects on delivery, affordability of the target beneficiaries and housing situations in Nigeria. Past studies highlight the relationship between project cost management systems (CMS) and cost performances. However, extensive studies exploring the CMS for LcH project delivery in Nigeria are rare. Apparently, no contemporary attempts are made to proffer appropriate and well-developed systematic solutions indicating possible continuing trends of poor cost management and performances in LcH project delivery. Given this discovery, this research seeks to develop a cost management system model (CMSM) for LcH project delivery in Nigeria. Empirical investigations explore the concepts of LcH project delivery, project cost management system (CMS) and implementation success factors (IMSF). The research leans towards an interpretivism perspective. It adopts a case study strategy and employs a sequential mixed method procedure for data collection and analysis at different phases of the research. A mix of focus group, semi-structured interviews, and questionnaires facilitated data collection and thematic- content analysis and statistical analysis (percentages, relative agreement index, Kruskal-Wallis, and exploratory factor analysis) for data analysis. Research findings reveal that popular CMS employed by the Project Management Teams (PMT) are incapable of delivering effective LcH project cost performances following three key constraints: difficulty to effectively set target cost, plan and perform real-time project cost monitoring and control, creating rooms for variations and overruns. These limitations were traceable to inappropriate use of cost management techniques, process approach alongside 18 implementation barriers. Integrating Target costing, Earn value analysis, a cost-design-control process approach and consideration of three key IMSF namely effective team qualities, effective information and management actions and stable operational environment were identified measures to improve current CMS efficacy. The research findings were used to develop the CMSM and its operational guide employing three modelling techniques: conventional process modelling, interpretive structural modelling (ISM) and the interpretive ranking process (IRP). These modelling techniques enhanced the design and understanding of the contextual relationships between the techniques, process, and IMSF in the CMS. The IRP and ISM used in this study are novel contributions to construction research, particularly in the area of LcH project cost management. The validation of the CMSM shows its capability to facilitate improved project cost management towards effective cost performances of LcH projects. The CMSM will assist the PMT to set effectively, plan, monitor, and control costs in LcH project delivery in Nigeria.