Sobel test

In statistics, the Sobel test is a method of testing the significance of a mediation effect. The test is based on the work of Michael E. Sobel,[1][2] and is an application of the delta method. In mediation, the relationship between the independent variable and the dependent variable is hypothesized to be an indirect effect that exists due to the influence of a third variable (the mediator). As a result when the mediator is included in a regression analysis model with the independent variable, the effect of the independent variable is reduced and the effect of the mediator remains significant. The Sobel test is basically a specialized t test that provides a method to determine whether the reduction in the effect of the independent variable, after including the mediator in the model, is a significant reduction and therefore whether the mediation effect is statistically significant.

  1. ^ Sobel, Michael E. (1982). "Asymptotic Confidence Intervals for Indirect Effects in Structural Equation Models". Sociological Methodology. 13: 290–312. CiteSeerX 10.1.1.452.5935. doi:10.2307/270723. JSTOR 270723.
  2. ^ Sobel, Michael E. (1986). "Some New Results on Indirect Effects and Their Standard Errors in Covariance Structure". Sociological Methodology. 16: 159–186. doi:10.2307/270922. JSTOR 270922.