How to decide degrees of freedom and prior variance in HB reg depending upon the data set?

Question

how to decide the df and prior variance in HB reg for doing regression modelling depending upon the data set , what impact different values will have on the results ?
Version 3.0.2

Answer 1

The prior degrees of freedom and prior variance control how much the HB algorithm tends to favor the upper or lower models.  The defaults provided seem in practice to provide a good balance, and we generally don't recommend changing them.  The need to change them is reduced with larger sample sizes.

The HB-Reg manual describes the impact of both variables on pages 15-16.