“…The validity of this theoretical perspective has been investigated in eighteen studies (see table 4). Measures of competition include the number of suppliers in a local market (e.g., Bradley, Jones, and Millington 2001;Christensen and Sachs 1980;Staley and Blair 1995), the distribution of market shares (e.g., Borland and Howsen 1992;Grosskopf et al 2001), rivalry between public and private suppliers (e.g., Arum 1996;Domberger, Hall, and Li 1995), and service managers' perceptions of the intensity of competition (D'Aunno, Hooijberg, and Munson 1991). The evidence on the impact of competition on service performance is very mixed.…”