MANCOVA MANOVA_assumptions_ heterogeneity of regression slopes


New Member
Hallo there :wave:,

I am examining the difference in illness models (by asking several Likert scale type questions: DV) for refugees (n=100) and non-refugees (IV)(n=100). In addition, we asked about several confounding variables / covariates (demographic data). I hypothesis that the illness models (question answers) will be significantly different for my refugees and non- refugees. Moreover, I want to look at the influence/ the relationship of my covariates and the model.

Some items of my dataset do not fulfil the requirement of homogeneity of regression slops. I was wandering how I can best describe the relationship of the covariate and DV for those items. I am aware that if I use a MANCOVA/ANCOVA regardless of this assumption violation, this will increase the TYPE II Error.

I have read about Johnson Neyman procure. It seems complicated to me.

Can I calculate a regulare MANOVA/ANOVA for the items, that do not fulfil the assumption of homogeneity of regression slopes (not enter the covariate)? And then check the way the covariate influences the DV by doing a regression only (e.g. linear regression)?

I am not aware of a valid method. Does anyone have experience with heterogeneity of regression slopes?

Thank you for your help :yup: