I have an unbalanced panel (3000 firms) for the period 1970-1976. However, a
few firms have missing values for some years. The number of such firms is
very few. When I tsset the time variable, Stata naturally states:
year, 1970 to 1976, but with gaps
My question is (a) does Stata's xtreg or xtabond or other panel data
regression techniques ignore such observations? (b) what is the downside of
such missing values?