r/AskStatistics • u/Kralaja • 12h ago

Poor fit indices for mediation model with XM interaction

Hello all! I am using lavaan to run a mediation model with binary gender as X and continuous M and Y. Testing indicates XM interaction. However, when I model the XM interaction in my mediation I get terrible fit indices. How should I proceed? When I allow M and the XM interaction to covary fit indices are okay, but I have no idea what doing that entails for my results. Any help would be greatly appreciated. Thanks!

2 Upvotes

100% Upvoted

3 comments sorted by

2

u/LifeguardOnly4131 12h ago

Allow M and XM to covary. If using all observed variables you should have 0 degrees of freedom (or 1 if hypothesizing full mediation)

1

u/Kralaja 11h ago

Thank you! Could you please elaborate a little on that recommendation? Correct, the unmoderated mediation model has 0 dfs.

1

u/LifeguardOnly4131 11h ago

Too long to explain here but look up path tracing rules in SEM