Abstract
This article explores methodological issues surrounding attempts to measure the impact of business service expertise on the performance, profitability and competitiveness of client companies. The authors use a survey of small and medium-sized enterprises (SMEs) in England as well as case studies of individual firms. The essay makes two methodological points. First, it is possible to identify a positive impact of business service expertise on client performance, but impossible to isolate such impacts from other management variables, for example the competence of the management team. Secondly, the timing of a corporate interview or data collection process influences the nature of the material collected. The only way to solve the problem of a time-specific understanding of a corporate event is through longitudinal research.