Please use this identifier to cite or link to this item: http://hdl.handle.net/10419/125012
Authors: 
Lechner, Michael
Rodríguez-Planas, Núria
Fernández-Kranz, Daniel
Year of Publication: 
2015
Series/Report no.: 
IZA Discussion Papers 9490
Abstract: 
We show that the OLS and fixed‐effects (FE) estimators of the popular difference-in-differences model may deviate when there is time varying panel non-response. If such non-response does not affect the common-trend assumption, then OLS and FE are consistent, but OLS is more precise. However, if non-response is affecting the common-trend assumption, then FE estimation may still be consistent, while OLS will be inconsistent. We provide simulation as well as empirical evidence for this phenomenon to occur. We conclude that in case of unbalanced panels, deviating OLS and FE estimates should be considered as evidence that non‐response is not ignorable for the differences-in-differences estimation.
Subjects: 
difference-in-difference estimation
attrition
panel estimation
balanced panel
unbalanced panel
JEL: 
C21
C31
Document Type: 
Working Paper

Files in This Item:
File
Size
324.22 kB





Items in EconStor are protected by copyright, with all rights reserved, unless otherwise indicated.