Hi, I am Fathima, a PhD candidate, doing my last minute data analysis of my research project.
I did an intervention to preschool children to improve their healthy food knowledge and preferences.
My study included three study groups (control, intervention type 1 and intervention type 2).
The baseline characteristics of my study groups differ by ethnicity, caregiver education level and caregiver income levels (each has 3 categories).
But the baseline and post assessment values of outcome variables (means were compared using KruskallWallis test) did not differ between the categories of all three covariates mentioned above.
This is a 6 week intervention, so these covariates are time invariant, hence not sure do I need to consider them for my model.

I found codes for DID analysis with as well as without covariates. But those with dichotomous covariates or continuous covariates.
But for covariates, do I need to make dummy variables? I am not sure. Searched a lot, can't find.

Please advice.

Thank you


Fathima