TY  - JOUR
AU  - Pakes,Ariel
TI  - Aggregation Effects And Panel Data Estimation Problems: An Investigationof the R&D Intensity Decision
JF  - National Bureau of Economic Research Working Paper Series
VL  - No. 344
PY  - 1979
Y2  - May 1979
UR  - http://www.nber.org/papers/w0344
L1  - http://www.nber.org/papers/w0344.pdf
N1  - Author contact info:
Ariel Pakes
Department of Economics
Harvard University
Littauer Room 117
Cambridge, MA 02138
Tel: 617/495-5320
Fax: 617/496-7352
E-Mail: apakes@fas.harvard.edu
AB  - This paper considers why the determinants of the inter- and intra-industry variance in R&D intensity in U.S. manufacturing differ markedly even though response parameters are similar across industries. A similar aggregation effect is noted by Grunfeld and Griliches (1960), and this paper gives that effect operational content in terms of grouped data estimation procedures. Observationally equivalent aggregation results can be generated by errors in variables models (see Aigner and Goldfeld [1974]).A later section considers specifications which identify the empirical importance of both these problems. Finally, a summary of the empirical results on the determinants of R&D intensity is provided.
ER  -