panel variable: country_id (strongly balanced) time variable: year, 2010 to 2011 delta: 1 unit means every panel has the same time periods. If some years are missing, you will see "unbalanced." Handling Unbalanced Panels Unbalanced panels are common (e.g., firms that enter or exit the sample). Stata handles them gracefully, but you must understand the implications for estimation.
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 union_panel.dta xtset id year xtsum wage union experience
regress wage experience union i.year, vce(cluster id) Clustering at the panel level is standard practice in economics. Controlling for year-specific shocks: