What is a main effect?

A main effect is a measure of the overall impact or relationship of a single independent variable on a dependent variable, while holding all other independent variables constant. It is typically tested in hypothesis testing and can be either significant or non-significant. A significant main effect suggests that the independent variable has a significant impact on the dependent variable, while a non-significant main effect suggests that the independent variable has no impact on the dependent variable. Main effects are commonly analyzed in analysis of variance (ANOVA) and regression analyses.