Abstract
In this paper, we study the least squares (LS) estimator in a linear panel regression model with unknown number of factors appearing as interactive fixed effects. Assuming that the number of factors used in estimation is larger than the true number of factors in the data, we establish the limiting distribution of the LS estimator for the regression coefficients as the number of time periods and the number of crosssectional units jointly go to infinity. The main result of the paper is that under certain assumptions, the limiting distribution of the LS estimator is independent of the number of factors used in the estimation as long as this number is not underestimated. The important practical implication of this result is that for inference on the regression coefficients, one does not necessarily need to estimate the number of interactive fixed effects consistently.
Original language  English 

Pages (fromto)  15431579 
Number of pages  37 
Journal  Econometrica 
Volume  83 
Issue number  4 
DOIs 

Publication status  Published  2015 Jul 1 
Bibliographical note
Publisher Copyright:© 2015 The Econometric Society.
All Science Journal Classification (ASJC) codes
 Economics and Econometrics