what is a moderator variable

In statistics and regression analysis, a moderator variable is a third variable that affects the strength or direction of the relationship between two other variables). It is also known as an effect modifier or simply a moderator. The effect of a moderating variable is characterized statistically as an interaction, which can be a categorical or continuous variable that is associated with the direction and/or magnitude of the relation between dependent and independent variables). Specifically, within a correlational analysis framework, a moderator is a third variable that affects the zero-order correlation between two other variables, or the value of the slope of the dependent variable on the independent variable). In analysis of variance (ANOVA) terms, a basic moderator effect can be represented as an interaction between a focal independent variable and a factor that specifies the appropriate conditions for its operation). Moderating variables can be qualitative or quantitative, and they can affect the relationship between two variables in many different ways, such as strengthening, weakening, or negating the relationship. Moderators are important because they often help researchers see beyond what is happening between two variables by seeing why it is happening or why it isnt happening.