Research methodology
The hypotheses can be represented by the structural equation model shown in Figure 1. To operationalize the SS, BSE, and SBSR success constructs, an initial list of variables was identified based on the literature. This was compared with company manuals provided by two prominent manufacturing firms with close relationships with key suppliers. Based on these sources, a revised list was developed and reviewed by ten industry professionals to ensure the variables were an accurate representation of industry practice. The revised survey instrument was further pre-tested by a different group of 20 industry professionals. As a result, seven indicators of BSE, 14 SS criteria, and four measures of relationship success were identified (see Appendix). A five-point Likert scale was developed for each item that reflected the extent to which tactics used by the buyer to select and engage in relationships with suppliers were considered important to their sourcing activities, or the extent to which the relationships were successful in helping the buyer achieve its goals. In the absence of consensus regarding how to assess business performance in cross industry studies (Narasimhan and Nair, 2005; Tan et al., 1998), five commonly used measures of performance reflecting financial, market, and product performance, were identified. Five-point Likert scales were developed for each that sought information on the performance of the responding โรงงาน relative to that of its major competitors (see Appendix).