Stata Panel Data Direct

To check balance explicitly:

Why does this matter? Because panel data allows you to control for unobserved heterogeneity—the "invisible" variables that differ across entities but remain constant over time. For example, when studying the impact of education policy on test scores, panel data can control for inherent differences in school quality or regional culture that you cannot measure directly.

xtreg wage experience union i.year, fe robust Or with vce(cluster id) :

eststo: xtreg wage experience union i.year, fe eststo: xtreg wage experience union i.year, re esttab using panel_results.rtf, replace mtitles("FE" "RE") se For interpretation, compute marginal effects:

Use pooled OLS as a baseline, but rarely as a final model. Fixed effects removes all time-invariant unobserved heterogeneity by de-meaning the data. It answers: Within a worker, how does changing union status affect wage?

xtreg wage educ experience union i.year, re – Deciding between FE and RE: