Hi everyone¡

I have cluster data from a School District ( 2000 Workers nested in 25 Schools), I have a continuous dependent variable and an independent variable, and several dichotomous covariates (at the individual and group level)
I am running Mixed in Stata 16. The null model's ICC is low (0.036), but the LR test vs. linear model suggests that the two-level model offers a significantly better fit to the data than the single-level model. Adding the first group level variable (variable at the School level) works the same...meaning that ICC is low. Still, the LR test vs. linear model suggests that the two-level model offers a significantly better fit to the data than the single-level model. When adding most group-level variables the ICC looks very odds (I suppose extremely low: 7.03e-16 ) and the LR test vs. linear model suggests that the two-level model does not offer a significantly better fit to the data than the single-level. My questions:
-How should I interpret an ICC value of: 7.03e-16
-Should I use standard regression and skip clustering the data?


Thanks, ¡¡¡