COTS-Based Systems (CBS) development focuses on building large software systems by integrating previously existing software components. CBS success depends on successful evaluation and selection of Commercial-Off-The- Shelf (COTS) software components to fit customer requirements. Literature shows that successful selection of offthe- shelf systems to fit customer requirements remains problematic. This paper presents the outcome of a study aimed at using a social-technical approach to identify and classify processes (including traditional and soft factors) that support COTS software selection. The identified factors and lessons learnt from case study assisted in elaborating and further development of Social-Technical Approach to COTS Evaluation framework (STACE).