Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-27T18:17:18.332Z Has data issue: false hasContentIssue false

ADDING REGRESSORS TO OBTAIN EFFICIENCY

Published online by Cambridge University Press:  01 February 2009

Sung Jae Jun*
Affiliation:
Pennsylvania State University
Joris Pinkse
Affiliation:
Pennsylvania State University
*
*Address correspondence to Sung Jae Jun, CAPCP, Department of Economics, 608 Kern Graduate Bldg., University Park, PA 16802, USA; e-mail: [email protected].

Abstract

It is well known that in standard linear regression models with independent and identically distributed data and homoskedasticity, adding “irrelevant regressors” hurts (asymptotic) efficiency unless such irrelevant regressors are orthogonal to the remaining regressors. But we have found that under (conditional) heteroskedasticity “irrelevant regressors” can always be found such that one can achieve the asymptotic variance of the generalized least squares estimator by adding the “irrelevant regressors” to the model.

Type
NOTES AND PROBLEMS
Copyright
Copyright © Cambridge University Press 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Aitken, A. (1935) On least squares and linear combination of observations. Proceedings of the Royal Society of Edinburgh 55, 4248.CrossRefGoogle Scholar
Davidson, R. & MacKinnon, J.G. (2004) Econometric Theory and Methods. Oxford University Press.Google Scholar
Delgado, M. (1992) Semiparametric generalized least squares in the multivariate nonlinear regression model. Econometric Theory 8, 203240.CrossRefGoogle Scholar
Greene, W.H. (2000) Econometric Analysis, 4th ed.Prentice-Hall.Google Scholar
Harvey, A. (1976) Estimating regression models with multiplicative heteroscedasticity. Econometrica 44, 461465.CrossRefGoogle Scholar
Magnus, J.R. & Durbin, J. (1999) Estimation of regression coefficients of interest when other regression coefficients are of no interest. Econometrica 67, 639643.CrossRefGoogle Scholar
Robinson, P.M. (1987) Asymptotically efficient estimation in the presence of heteroskedasticity of unknown form. Econometrica 55, 875891.CrossRefGoogle Scholar