Introduced in recent versions, the Correlated Random Effects model, implemented via xtreg, cre , offers a more flexible alternative to RE. It allows the panel-level effects to be correlated with the regressors by including panel-level means of the time-varying covariates, bridging the FE and RE approaches.
Crucially, Stata's CRE implementation works for , thanks to Wooldridge's extension of Mundlak's original result. stata panel data exclusive
* Syntax: xtset panelvar timevar [, options] xtset firm_id year Use code with caution. Introduced in recent versions, the Correlated Random Effects
To decide between FE and RE, Stata provides an exclusive diagnostic procedure: * Syntax: xtset panelvar timevar [, options] xtset
After estimation, use estat abond to test for serial correlation in the first-differenced residuals and estat sargan to test overidentifying restrictions.
With a low p-value from the Hausman test, Aris confirms that the Fixed Effects model is the only way to tell the true story of startup success. He publishes his findings, showing that while luck matters, the "exclusive" trends found within the panel data prove that consistent investment in talent is the ultimate differentiator.
, and then uses lagged levels of the endogenous variables as instruments.