Economic versus physical input measures in the analysis of technical efficiency in fisheries

The measurement of technical efficiency requires the estimation of an appropriate production frontier. This is based on a set of inputs that are assumed to influence the level of output. Deviations from this frontier production function are separated into random variation and inefficiency. However, mis-specification of the production function through the use of inappropriate input measures may result in a bias in the measures of inefficiency. In fisheries, production is generally assumed to be a function of stock size, fishing time and the level of physical inputs employed. Defining the appropriate levels of physical inputs, however, is not straightforward, and several alternative measures are available. While economic measures of capital are more intuitively appealing, physical measures are generally readily available and hence less costly to collect. In this study, technical efficiency is measured for three fleet segments operating in the North Sea using three different gear types. The effects of using different measures of capital in the production frontier on the efficiency estimates are examined.