The Fixed Effects model controls for all time-invariant, unobserved characteristics of your entities (e.g., cultural factors, innate ability, geographic location). It only examines variation within an entity over time. xtreg y x1 x2, fe Use code with caution. Random Effects (RE)
Panel data contains observations on multiple entities (individuals, firms, countries) observed over multiple time periods. Key Characteristics Cross-sectional dimension (
Decomposes summary statistics into within and between components xtline Generates time-series line graphs for panel units xtreg ..., fe Estimates a Fixed Effects panel regression xtreg ..., re Estimates a Random Effects panel regression hausman Performs the test to choose between FE and RE models
Each row represents a single entity-time observation. Stata requires the long format for panel data analysis.
Variance within the same entity over time (time-series variation). stata panel data
This breakdown is crucial for deciding which panel model is most appropriate for your research question. 3. xtline
The big question in panel analysis is whether to use or Random Effects (RE) . Panel Data Analysis Fixed and Random Effects using Stata
Autocorrelation makes standard errors deceptively small. Test for it using the Wooldridge test via the xtserial command: ssc install xtserial xtserial y x1 x2 Use code with caution. The Universal Fix: Robust Standard Errors
I can provide the specific code and troubleshooting steps for your exact model. Share public link The Fixed Effects model controls for all time-invariant,
Panel data estimation typically revolves around three core frameworks: Pooled OLS, Fixed Effects, and Random Effects. Pooled OLS Regression
: Panel data, Stata, fixed effects, random effects, FDI, economic growth
The null hypothesis of the Hausman test is that the preferred model is Random Effects vs. the alternative Fixed Effects. It essentially tests whether the unique errors are correlated with the regressors. How to Run the Hausman Test in Stata
This article is your definitive guide to analysis. Whether you are a graduate student wrestling with your first panel dataset or a researcher refining a complex model, this guide will walk through preparation, exploration, modeling, diagnostics, and advanced techniques. Random Effects (RE) Panel data contains observations on
For long panels (large T):
Before diving into Stata panel data analysis, it's essential to understand some key concepts:
| Feature | Pooled OLS | Fixed Effects (FE) | Random Effects (RE) | | :--- | :--- | :--- | :--- | | | reg y x | xtreg y x, fe | xtreg y x, re | | Assumption | No individual effects | $\alpha_i$ correlated with $x$ | $\alpha_i$ NOT correlated with $x$ | | Time-Invariant Vars? | Yes | No (Dropped) | Yes | | Efficiency | N/A | Low | High | | Best For | Preliminary analysis | Causal inference (observational) | Efficiency / Random sampling |
A unique variable identifying each cross-sectional unit (e.g., country_id , firm_id , person_id ).