Compară metode

	Testul de rădăcină unitară pentru paneluri Breitung	Testul Fisher pentru rădăcini unitare în paneluri
Domeniu	Econometrie	Econometrie
Familie	Hypothesis test	Hypothesis test
Anul apariției	2000	1999
Autorul original	Jörg Breitung	G. S. Maddala & Shaowen Wu
Tip	Nonparametric panel unit-root test	Nonparametric combination-of-p-values panel unit-root test
Sursa seminală	Breitung, J. (2000). The local power of some unit root tests for panel data. Advances in Econometrics, 15, 161–177.	Maddala, G. S., & Wu, S. (1999). A comparative study of unit root tests with panel data and a new simple test. Oxford Bulletin of Economics and Statistics, 61(S1), 631–652.
Denumiri alternative	Breitung Panel Unit-Root Test, Breitung (2000) Test, Breitung Nonparametric Panel Unit-Root Test, Breitung Panel Birim Kök Testi	Maddala-Wu Test, Fisher-type Panel Unit-Root Test, MW Panel Unit-Root Test, Fisher Panel Birim Kök Testi
Înrudite	3	3
Rezumat	The Breitung test, introduced by Jörg Breitung in 2000, is a nonparametric panel unit-root test designed to assess whether all cross-sectional units in a balanced panel share a common unit root. Unlike competing first-generation tests, it avoids bias-correction terms that depend on lag selection or kernel bandwidth estimation, thereby preserving local power under a homogeneous alternative. It is widely used in macroeconometrics and finance when the researcher suspects cross-sectional homogeneity in the autoregressive structure.	The Fisher-type (Maddala-Wu) panel unit-root test, introduced in 1999, combines individual-level ADF unit-root p-values using Fisher's chi-squared meta-analytic framework to produce a single panel-level test statistic. Unlike the Levin-Lin-Chu approach, it does not impose a common autoregressive parameter across cross-sections, making it a natural choice for heterogeneous panels in macroeconomics, finance, and regional economics.