Qualitative system dynamics approach to modelling cost escalation determinants in Nigerian public sector projects

Purpose Cost escalation has been identified as one of the most significant challenges and recurring issues in the delivery of social and economic infrastructure in the Nigerian public sector. Like many other countries in the Global South, the Nigerian public sector projects suffer from poor cost performance. Thus, this study aims to analyse the dynamics of construction cost escalation determinants and produced a conceptual system dynamic model that captures the intricate interactions among these determinants. Design/methodology/approach This study includes a literature review and qualitative approach using semi-structured interviews. Data were obtained from 17 stakeholders involved in the delivery of Nigeria public sector projects, including Project managers, Architects, Civil engineer, Quantity surveyors and Construction managers. The data were analysed using a coding framework informed by case study approach, the principles of thematic analysis and saliency analysis framework, enabling the modelling of intricate interactions among various determinants of cost escalation. Findings The findings revealed a complex and dynamic interaction among the determinants, indicating that an isolated solution to cost escalation, particularly in developing countries like Nigeria, is unlikely. Instead, a holistic, system-oriented approach that considers the interplay of multiple determinants is necessary for effective cost escalation management. One of the determinants identified was the lack of technical competence among professionals involved in the delivery of public sector construction projects. In addition, the analysis of the causal loop diagram revealed intervention points in the project delivery process to counter cost escalation. This study postulates that a key intervention strategy involves enhancing the competencies of construction professionals through synergistic collaboration between various stakeholders: public sector entities, professional bodies, statutory regulatory bodies and policymakers. Research limitations/implications As the findings are rooted in Nigerian public construction projects, their relevance to privately financed projects might be limited. Also, the study focuses solely on the construction stage, without extending to the post-construction phase. Furthermore, the themes and their causal links were derived from viewpoints of experts from the Nigerian context. Future studies could enhance the external validity of the research results by examining their applicability in other contexts and by integrating the later phases of public sector construction projects, such as facilities management operation, to offer a more holistic view of the problem. Originality/value This study presents a collaborative and holistic approach to address cost escalation in Nigerian public sector projects by modelling the complex interactions among various determinants influencing cost escalation within a dynamic framework and identifying critical intervention points in the project delivery process.