WK 8 Flashcards
What is mediation?
Mediation is when a predictor X, has an effect on an outcome Y, via a mediating variable M
What does the mediator do?
The mediator transmits the effect of X to Y
What is moderation?
Moderation is when a moderator z modifies the effect of X on Y
What is the indirect effects of X on Y?
The indirect effects of X on Y are those transmitted via the mediator
What is the direct effect of X on Y?
The direct effect of X on Y is remaining effect of X on Y
What are the limitations of traditional methods for mediation?
- low power
- very cumbersome for multiple mediators, predictors, or outcomes
-you don’t get an estimate of the magnitude of the indirect effect
What can the total effect be interpreted as?
The total effect can be interpreted as the unit increase in Y expected to occur when X increases by one unit.
What can the indirect effect be interpreted as ?
The indirect effect can be interpreted as the unit increase in Y expected to occur via M when X increases by one unit
What can the direct effect be interpreted as?
The direct effect can be interpreted as the unit increase in Y expected to occur with a unit increase in X over and above the increase transmitted by M
What is the assumption with assessing statistical significance of indirect effects?
Assume normal sampling distribution
Why code the total effect in lavaan?
We can assess the statistical significance of the total effect
Why is it useful to code the total effect in lavaan?
It is useful because sometimes the direct and indirect effects are not individually significant but the total effect it.
What is proportion mediation?
how much of the total effect is taken up by the indirect effect
What is an assumption of path analysis models?
Assumption that the paths represent causal effects
How do you do path analysis in R?
using the sem() function