Hello all,

I'm working with a fixed effects panel data model (individual FE). I have a number of individual-level independent variables. It is obvious that many of these individual-level variables change over time or each panelist (e.g. age). However, I have one individual-level variable that may or may not change over time, depending on the individual (STATA does not reject due to collinearity). I would like to determine exactly how many panelists experienced any change in this independent variable. What code could I use?