In an experiment with 5 technicians from different companies, we investigated effects of new equipments. The interested response variable is categorical.
One thing I am considering is that the technician effect is a random effect. But it's hard to include a random effect in the multinomial logistic model. If there is not much difference, I would enter the effect as a fixed effect. So my question:
How bad is considering a random effect as a fixed effect?
From my old statistics class, I can see variability of response variable will be underestimated because of the true random effect and thus might affect statistical tests in the model. But I am not sure how bad it will be.