A simulation study was conducted to evaluate the performance of three tests of mediation: the bias-corrected and accelerated bootstrap (Efron & Tibshirani, 1993), the asymmetric confidence limits test (MacKinnon, 2008), and a multiple regression approach described by Kenny, Kashy, and Bolger (1998). The evolution of these methods is reviewed and current recommendations for assessing mediation are discussed (Frazier, Tix, & Barron, 2004; Preacher & Hayes, 2004; Mallinckrodt, Abraham, Wei, & Russell, 2006). The three tests of mediation were evaluated according to three criteria that should be of interest to researchers as they choose among methods for testing mediation hypotheses: the statistical standard, the conceptual standard and the pragmatic standard. The statistical properties of the three tests of mediation were evaluated by assessing the Type I error rates and power of the tests. The conceptual standard was assessed by evaluating which method best captures the conceptual meaning of mediation. The pragmatic standard was assessed by evaluating which method was the minimally sufficient analysis to test the most basic, three-variable mediation model. I argue that for the most basic mediation model, the multiple regression approach described by Kenny et al. (1998) provides the best balance of Type I error and power among the three methods investigated; is a conceptually sound test of mediation in that it tests the significance of each link in the hypothesized causal chain; and is the minimally sufficient analysis for assessing mediation. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]