Glossary
Moderation analysis
What is moderation analysis?
Moderation analysis tests whether a relationship or treatment effect changes across levels of another variable, often using an interaction term in a regression model.
Interpretation
The analysis estimates the interaction and can describe the relationship at selected moderator values. Baron and Kenny’s methodological paper distinguishes this conditional relationship from an indirect effect through a mediator.
How the interaction model works
A basic regression model includes the predictor, the moderator, and their product as an interaction term. The interaction describes how the predictor’s estimated relationship with the outcome changes with the moderator. Examining that relationship at selected moderator values is often called simple slopes analysis.
Example and limits
Suppose a company asks whether training helps new hires more than experienced staff. Moderation analysis estimates that difference, with uncertainty. A subgroup with a nonsignificant estimate has not thereby been shown to receive no benefit. A proposed targeting rule needs appropriate evidence, rather than being inferred solely from which subgroup p-values cross a threshold.