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Were Cobb and Douglas Prejudiced? A Critical Re-analysis of their 1928 Production Model Identification


  • Cornelis A. Los

    (Kent State University)


In 1928 Cobb and Douglas (C&D) presented a system analysis which established the first empirically identified production model, which forms the foundation for Solow's growth theory and research into productivity growth factors, such as 'technological progress ' and 'human capital development '. C&D claimed that their production model ('function') showed neutral economies of scale, i.e., constant returns to scale, with a labor production elasticity of 3/4 and a capital production elasticity of 1/4. A simple CLS analysis shows that C&D's data were incorrectly identified by an (n,q)=(3,1) linear model. C&Ds claim that their neutral 'constant returns of scale ' was the inevitable scientific conclusion of their analysis was also incorrect, since that conclusion is strictly determined by their subjectively chosen projection direction. In fact, the data shows that with their model and identification technology constant, increasing and diminishing returns to scale are all three compatible with the uncertain data. Their (n,q) = (3,1) model was never identified with an acceptable level of scientific accuracy, with a maximum coefficient value variation of 212%). In contrast, a simple two-equation (n,q) = (3,2) system model can be accurately identified from C&Ds data set, with an acceptable level of accuracy, with a maximum coefficient value variation of 7.4%).

Suggested Citation

  • Cornelis A. Los, 2005. "Were Cobb and Douglas Prejudiced? A Critical Re-analysis of their 1928 Production Model Identification," Econometrics 0502013, University Library of Munich, Germany.
  • Handle: RePEc:wpa:wuwpem:0502013
    Note: Type of Document - pdf; pages: 16

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    References listed on IDEAS

    1. Robert M. Solow, 1956. "A Contribution to the Theory of Economic Growth," The Quarterly Journal of Economics, Oxford University Press, vol. 70(1), pages 65-94.
    2. Los, Cornelis A., 1999. "Galton's Error and the under-representation of systematic risk," Journal of Banking & Finance, Elsevier, vol. 23(12), pages 1793-1829, December.
    3. Cornelis A. Los, 1991. "A Scientific View of Economic Data Analysis," Eastern Economic Journal, Eastern Economic Association, vol. 17(1), pages 61-71, Jan-Mar.
    4. Cornelis A. Los, 1987. "Identification of a linear system from inexact data: a three variable example," Research Paper 8703, Federal Reserve Bank of New York.
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    More about this item


    System identification; growth theory; production elasticities; projections; Complete Least Squares; noisy data;

    JEL classification:

    • C1 - Mathematical and Quantitative Methods - - Econometric and Statistical Methods and Methodology: General
    • C2 - Mathematical and Quantitative Methods - - Single Equation Models; Single Variables
    • C3 - Mathematical and Quantitative Methods - - Multiple or Simultaneous Equation Models; Multiple Variables
    • C4 - Mathematical and Quantitative Methods - - Econometric and Statistical Methods: Special Topics
    • C5 - Mathematical and Quantitative Methods - - Econometric Modeling
    • C8 - Mathematical and Quantitative Methods - - Data Collection and Data Estimation Methodology; Computer Programs

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