ASSESSMENT ON THE EFFECT OF DESIGN VARIATION ON BUILDING PROJECT PERFORMANCE IN MINNA, NIGERIA

ABSTRACT This study assesses the effect of design variations on building project performance in Minna, Nigeria, with a focus on cost, schedule, and quality. Using a survey research design, data were collected from 102 professionals involved in public building projects in the region. The analysis, conducted using the Mean Item Score (MIS) method, reveals that design variations significantly increase project costs, cause schedule delays, and negatively impact project quality. The study identifies key causes of design variations, including client-initiated changes, unforeseen site conditions, and regulatory compliance issues, all of which have a strong influence on project performance. Furthermore, the findings highlight that comprehensive initial planning, the use of Building Information Modeling (BIM), and the involvement of experienced design and construction teams are the most effective strategies for minimizing design variations. These results emphasize the importance of early stakeholder engagement, regular risk assessments, and efficient communication to mitigate the negative impacts of design variations on building project performance in Minna. Recommendations for improving project performance include the adoption of modern technologies, detailed scope definition, and proactive risk management.