Assessing the effectos of measurement errors on the estimation of the production function

This article explores the reasons why GMM estimators of production function parameters are generally found to produce unsatisfactory results. I attribute this finding to the inaccurate construction of the variables used in production function analysis. In particular, I suggest that the problem lies in the use of common price deflators as well as in a capital variable that does not reflect the true flow of capital services because of short-run equilibrium effects. I show that the practice of using industry-wide deflators leads to lower scale estimates, mainly due to a relevant downward bias in the labour coefficient. At the same time, it introduces a large upward bias in estimating the elasticity of output with respect to technological innovation. Moreover, a significant improvement in the estimates of capital coefficients is obtained if the information on the degree of capacity utilization is adequately exploited.