For my master's dissertation I have some troubles in analyzing my panel data. I'm currently investigating the role of new executives on the tax rate of a company:
dependent variable: effective tax rate
independent variables: Size, R&D, year, new executive in last 2 years (dummy), ...
For every company I have data for the last 3 years, I would like to interpret my results as: Within a certain company, a change in executive has a X influence on the tax rate.
My problem is thus how I can control for this? I know that in STATA there is something to make the company fixed, however I do not find the correct way in spss...
Any suggestions or do I forget sth?