Sammenlign metoder

	Fourier Hausman-test	Instrumentalvariabel (IV) Metoden til Kausal Inferens
Fagområde	Økonometri	Sundhedsøkonomi
Familie	Regression model	Process / pipeline
Oprindelsesår	2000s–2010s	1990s (modern applications)
Ophavsperson	Extends Hausman (1978) using Gallant's (1981) Fourier flexible functional form; applied in panel/time-series settings by Christopoulos & Leon-Ledesma (2004) and subsequent literature	Angrist & Pischke (applied econometrics); rooted in econometric theory
Type	Specification / endogeneity test	Method
Oprindelig kilde	Christopoulos, D. K., & Leon-Ledesma, M. A. (2004). Current account sustainability in the US: What do we really know about it? Journal of International Money and Finance, 23(5), 821–840.	Angrist, J. D., & Pischke, J. S. (2009). Mostly Harmless Econometrics: An Empiricist's Companion. Princeton: Princeton University Press.
Aliasser	Fourier-Hausman endogeneity test, Fourier augmented Hausman test, nonlinear Hausman test, flexible Hausman specification test	IV, two-stage least squares, TSLS, causal estimation
Relaterede	5	3
Resumé	The Fourier Hausman test extends the classical Hausman endogeneity test by augmenting the regression with Fourier trigonometric terms — sines and cosines of time — so that the test remains valid even when the data-generating process contains smooth structural breaks or gradual nonlinearities that conventional linear specifications miss.	Instrumental variables (IV) is an econometric method to estimate causal effects when treatment or exposure is not randomly assigned and confounding is severe or unmeasured. IV relies on a third variable (instrument) that influences treatment but does not directly affect the outcome, allowing researchers to isolate the causal effect from the noise of confounding. Developed extensively in econometrics (Angrist & Pischke, 1990s–2000s), IV methods are increasingly used in health economics and health services research to leverage natural experiments and policy changes.