Analysis of Subcontractor Performance and Its Effect on Project Cost in the South South Nigeria

Subcontractor performance is a critical determinant of overall project outcomes in construction, with direct implications for cost, time, and quality objectives. This study analyses subcontractor performance and its effect on construction project costs in the South South geopolitical zone of Nigeria, focusing on building and civil engineering projects in Delta and Cross River States. A quantitative survey design was employed, with 84 quantity surveyors, main contractors, and project managers serving as respondents. Structured questionnaires and review of project cost records formed the data collection instruments. Data were analysed using relative importance index and regression analysis. Findings indicate that poor workmanship, delayed mobilisation, inadequate equipment, and labour disputes are the leading performance deficiencies among subcontractors. These deficiencies result in additional costs through rework, acceleration measures, and delay damages averaging 6.2% of subcontract value. The study finds that most main contractors in the region do not maintain systematic subcontractor prequalification frameworks, selecting subcontractors primarily based on price rather than demonstrated capability. Recommendations include the adoption of formal subcontractor prequalification and performance evaluation systems, mandatory inclusion of performance bonds in subcontract agreements, and improved monitoring by resident quantity surveyors. Professional bodies are urged to develop guidelines for subcontractor management applicable to the Nigerian construction context. This research addresses a gap in the South South's construction cost management literature. Keywords: subcontractor performance, project cost, construction management, South South Nigeria, prequalification