Institutional lock-in and circular procurement in the Nigerian construction industry: an interpretive structural analysis

Circular procurement is increasingly promoted as a mechanism for operationalizing circular economy (CE) principles in construction; however, adoption remains limited in many developing economies. Existing studies largely identify and rank barriers without explaining how such constraints interact structurally or shape the sequencing of interventions. This study examines the structural relationships among barriers to circular procurement in the Nigerian construction industry using a combination of interpretive structural modelling (ISM) and MICMAC analyses informed by expert judgement. Five barrier categories were validated through a focus group discussion session with 11 purposively selected construction professionals. ISM was applied to derive a hierarchical model, while MICMAC classified barriers according to driving and dependence power. The findings reveal a tightly coupled system in which all barriers exhibit strong mutual influence and fall within the linkage cluster. The inadequacy of government policies and initiatives emerges as the foundational constraint shaping organizational culture, procurement routines, stakeholder capabilities, and financial conditions. These reinforcing relationships indicate institutional lock-in around linear procurement practices. The study advances circular procurement scholarship by shifting from variable-centered barrier ranking to systems-based explanation and offers evidence-based guidance for sequencing institutional, organisational, and market-level interventions in developing economy construction contexts.