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Econometric Models for Count Data with an Application to the Patents-R&D Relationship


  • Jerry A. Hausman
  • Bronwyn H. Hall
  • Zvi Griliches


This paper focuses on developing and adapting statistical models of counts (non-negative integers) in the context of panel data and using them to analyze the relationship between patents and R&D expenditures. The model used is an application and generalization of the Poisson distribution to allow for independent variables; persistent individual (fixed or random) effects, and "noise" or randomness in the Poisson probability function. We apply our models to a data set previously analyzed by Pakes and Griliches using observations on 128 firms for seven years, 1968-74. Our statistical results indicate clearly that to rationalize the data, we need both a disturbance in the conditional within dimension and a different one, with a different variance, in the marginal (between) dimension. Adding firm specific variables, log book value and a scientific industry dummy, removes most of the positive correlation between the individual firm propensity to patent and its R&D intensity. The other new finding is that there is an interactive negative trend in the patents - R&D relationship, that is, firms are getting less patents from their more recent R&D investments, implying a decline in the "effectiveness" or productivity of R&D.

Suggested Citation

  • Jerry A. Hausman & Bronwyn H. Hall & Zvi Griliches, 1984. "Econometric Models for Count Data with an Application to the Patents-R&D Relationship," NBER Technical Working Papers 0017, National Bureau of Economic Research, Inc.
  • Handle: RePEc:nbr:nberte:0017 Note: PR

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    1. Lucas, Robert E, Jr & Prescott, Edward C, 1971. "Investment Under Uncertainty," Econometrica, Econometric Society, vol. 39(5), pages 659-681, September.
    2. Hansen, Lars Peter, 1982. "Large Sample Properties of Generalized Method of Moments Estimators," Econometrica, Econometric Society, vol. 50(4), pages 1029-1054, July.
    3. Lars Peter Hansen & Thomas J. Sargent, 1980. "Linear rational expectations models for dynamically interrelated variables," Working Papers 135, Federal Reserve Bank of Minneapolis.
    4. McCallum, Bennett T, 1976. "Rational Expectations and the Natural Rate Hypothesis: Some Consistent Estimates," Econometrica, Econometric Society, vol. 44(1), pages 43-52, January.
    5. Wallis, Kenneth F, 1980. "Econometric Implications of the Rational Expectations Hypothesis," Econometrica, Econometric Society, vol. 48(1), pages 49-73, January.
    6. Goodfriend, Marvin S., 1982. "An alternate method of estimating the Cagan money demand function in hyperinflation under rational expectations," Journal of Monetary Economics, Elsevier, vol. 9(1), pages 43-57.
    7. Hall, Robert E, 1988. "Intertemporal Substitution in Consumption," Journal of Political Economy, University of Chicago Press, vol. 96(2), pages 339-357, April.
    8. Long, John B, Jr & Plosser, Charles I, 1983. "Real Business Cycles," Journal of Political Economy, University of Chicago Press, vol. 91(1), pages 39-69, February.
    9. Kennan, John, 1979. "The Estimation of Partial Adjustment Models with Rational Expectations," Econometrica, Econometric Society, vol. 47(6), pages 1441-1455, November.
    10. N. Gregory Mankiw & Julio J. Rotemberg & Lawrence H. Summers, 1985. "Intertemporal Substitution in Macroeconomics," The Quarterly Journal of Economics, Oxford University Press, vol. 100(1), pages 225-251.
    11. Lucas, Robert E, Jr, 1978. "Asset Prices in an Exchange Economy," Econometrica, Econometric Society, vol. 46(6), pages 1429-1445, November.
    12. Lucas, Robert Jr, 1976. "Econometric policy evaluation: A critique," Carnegie-Rochester Conference Series on Public Policy, Elsevier, vol. 1(1), pages 19-46, January.
    13. Fumio Hayashi, 1980. "Estimation of Macroeconometric Models Under Rational Expectations: A Survey," Discussion Papers 444, Northwestern University, Center for Mathematical Studies in Economics and Management Science.
    14. Hansen, Lars Peter & Singleton, Kenneth J, 1982. "Generalized Instrumental Variables Estimation of Nonlinear Rational Expectations Models," Econometrica, Econometric Society, vol. 50(5), pages 1269-1286, September.
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