An extended Cobb-Douglas production function is developed and estimated in order to examine the extent to which the decline in measured productivity in underground coal mining can be attributed to (1) changes in safety conditions which reflect movement along a product transformation frontier relating safety and marketable output and (2) a shift downward of the entire transformation surface. The model incorporates work-related accidents as a joint output and accounts for the discrete nature of the technological choices available in underground mining. The results indicate that movements along the product transformation curve relating accidents and marketable output do not account for the decline in measured productivity. This decline instead reflects a shift downward of this frontier - a real decline in potential production of marketable output. The non-linear pattern in technological change parameters and differences in these parameters across technologies indicate that a variety of factors have influenced productivity trends including CMHSA and the 1974 contract between union and management. 14 references

This paper examines the extent of response errors in labor market survey data and explores the implications of such errors for economic analysis. Explicitly examined are responses to questions on industry, occupation, union status, hours worked, and wages. Analyses are based on two sources: (1) a special supplement to the January 1977 Current Population Survey that obtained data from workers and their employers and (2) an exact match of workers and their employers interviewed in the Employment Opportunity Pilot Project Survey. The dual nature of these surveys provides a basis for analyzing the effect of response error on a variety of economic analyses including the trade-off between wages and risk, the wage impact of unionism, and the sensitivity of wage-determination models to alternative responses to earnings questions.