An Investigation of Corruption Vulnerability in the Nigerian Construction Procurement System: A Systemic Analysis

Corruption in construction procurement is a systemic phenomenon driven by institutional, procedural, and behavioural vulnerabilities that interact in complex ways. This study conducts a comprehensive systemic analysis of corruption vulnerability in the Nigerian construction procurement system, identifying the structural weaknesses that enable corrupt practices and their quantifiable cost to public infrastructure delivery. A critical realist ontology underpins a mixed-method design employing 70 stakeholder interviews, analysis of 80 procurement audit reports, network analysis of procurement actor relationships, and participatory vulnerability mapping with 35 experienced practitioners. Systems thinking tools including causal loop diagrams and vulnerability mapping were applied. Findings identify 24 systemic corruption vulnerability points spanning needs assessment manipulation, specification inflation, bid collusion, evaluation manipulation, variation exploitation, and final account padding. Network analysis reveals that corruption in Nigerian construction procurement is not isolated but connected through reciprocal actor networks that create entrenched structural vulnerabilities resistant to single-intervention reform. The study estimates that systemic corruption adds between 22% and 38% to public construction costs annually at the national level. A Nigeria Construction Procurement Integrity Framework (NCPIF) is developed and validated through expert panel assessment. This research makes an original systemic and empirical contribution to anti-corruption scholarship in the construction sector globally. Keywords: corruption, procurement, systemic analysis, Nigeria, construction integrity