Σύγκριση μεθόδων

	Διαφορές-σε-Διαφορές Πολλαπλών Περιόδων (Σταδιακή DiD)	Διαχρονικά Δεδομένα Διαφορών σε Διαφορές (Panel DiD / TWFE)
Πεδίο	Αιτιακή Συμπερασματολογία	Αιτιακή Συμπερασματολογία
Οικογένεια	Regression model	Regression model
Έτος προέλευσης	2021	1985–2004
Δημιουργός	Callaway & Sant'Anna; Goodman-Bacon	Ashenfelter & Card (1985); codified by Angrist & Pischke (2009); serial correlation critique by Bertrand, Duflo & Mullainathan (2004)
Τύπος	Causal inference / panel regression	Causal inference / panel regression
Θεμελιώδης πηγή	Callaway, B., & Sant'Anna, P. H. C. (2021). Difference-in-differences with multiple time periods. Journal of Econometrics, 225(2), 200-230.	Angrist, J. D., & Pischke, J.-S. (2009). Mostly Harmless Econometrics: An Empiricist's Companion. Princeton University Press. ISBN: 978-0691120355
Εναλλακτικές ονομασίες	staggered DiD, multi-period DiD, staggered difference-in-differences, heterogeneous timing DiD	Two-Way Fixed Effects DiD, TWFE, Panel DiD, Panel Diff-in-Diff
Συναφείς	5	4
Σύνοψη	Multi-period Difference-in-Differences extends the classic two-period DiD framework to settings where units adopt treatment at different points in time. Formalised by Callaway and Sant'Anna (2021) and Goodman-Bacon (2021), it decomposes the overall treatment effect into group-time average treatment effects and addresses the bias that arises when conventional two-way fixed-effects regressions are applied to staggered adoption designs.	Panel Data Difference-in-Differences extends the classic two-period DiD design to settings with multiple units observed across many time periods. By absorbing unit-level fixed effects and time fixed effects simultaneously, it isolates the causal effect of a treatment or policy change while controlling for both time-invariant unit heterogeneity and common time shocks affecting all units.