Tuesday, February 13, 2007

Bergstrom, Rubinfeld and Shapiro, Econometrica 1982

"Micro-Based Estimates of Demand Functions for Local School Expenditures"

This paper uses the same Michigan survey data we saw in the Gramlich and Rubinfeld paper, but this one focuses on school expenditures and features a econometric technique to estimate a continuous demand function from a three category survey response.

The dependent variable in most of the Gramlich and Rubinfeld paper was per capita government spending, which had been backed out of survey responses where people were presented with the amount their municipality spent and asked to provide how much more or less they would like the municipality to spend. Here, respondents are asked what they think education spending should be: "more," "less," or "the same." The econometric move the authors are hawking here appears to be an MLE approach to converting this categorical answer into something continuous. It looks to me like they assume that individuals in different municipalities have the same tastes (conditional on their individual characteristics), and they use the variation in the actual spending across municipalities to identify the width of their indifference band. In other words, the width of the indifference band is another parameter in the likelihood model (along with coefficients on individual characteristics, which determine the expected value of the underlying continuous demand for public goods).

The alternative would have been to estimate ordered probit or something like that, but this would not have made full use of the fact that actual expenditures vary across municipalities. The authors want to get a demand function out of this data, and this is how they'll get it.

No comments: