What is the combined effect of two or more predictor variables on an outcome variable, often used to gauge moderation?

What is the combined effect of two or more predictor variables on an outcome variable, often used to gauge moderation?

• A. Main effect
• B. Interaction effect
• C. Mediator effect
• D. Covariate effect

Answer: (B)

When two predictors combine to influence an outcome in a way that depends on each other, that joint influence is called an interaction effect. It means the effect of one predictor on the outcome changes depending on the level of the other predictor. In moderation, a moderator variable alters the strength or direction of the relationship between a predictor and the outcome, which is detected by including an interaction term (the product of the two predictors) in the analysis. For example, imagine exam performance is predicted by study hours and prior knowledge. If the impact of study hours on performance is larger for students with high prior knowledge than for those with low prior knowledge, there is an interaction between study hours and prior knowledge. This isn’t simply additive; the combined effect differs across levels of the moderators. Main effects refer to the individual, averaged impact of each predictor when others are held constant. Mediator effects explain how or why a predictor influences the outcome, and covariates are controls used to account for other variables. The interaction captures how predictors work together to shape the outcome, which is the essence of moderation.

When two predictors combine to influence an outcome in a way that depends on each other, that joint influence is called an interaction effect. It means the effect of one predictor on the outcome changes depending on the level of the other predictor. In moderation, a moderator variable alters the strength or direction of the relationship between a predictor and the outcome, which is detected by including an interaction term (the product of the two predictors) in the analysis.

For example, imagine exam performance is predicted by study hours and prior knowledge. If the impact of study hours on performance is larger for students with high prior knowledge than for those with low prior knowledge, there is an interaction between study hours and prior knowledge. This isn’t simply additive; the combined effect differs across levels of the moderators.

Main effects refer to the individual, averaged impact of each predictor when others are held constant. Mediator effects explain how or why a predictor influences the outcome, and covariates are controls used to account for other variables. The interaction captures how predictors work together to shape the outcome, which is the essence of moderation.