Measuring Productive Efficiency: An Application to Illinois Strip Mines
将Farrell技术效率测量方法推广到伊利诺伊州露天煤矿样本，将效率分解为纯技术效率、投入拥挤和规模效率三个部分，发现煤矿整体效率较高，主要低效源于规模不当。
The purpose of this paper is to apply a generalized version of the Farrell measure of technical efficiency to a sample of Illinois strip mines. We disaggregate the original Farrell measure (which was designed to measure lost output or wasted inputs due to underutilization of inputs) into three mutually exclusive and exhaustive components: (1) a measure of purely technical efficiency, (2) a measure of input congestion (overutilization of some input(s)) and (3) a measure of scale efficiency. This approach has the advantage that it provides additional information on the sources of inefficiency of production, which should be useful to managers, in general, not only in strip mining. Simple linear programming techniques are derived and used in calculating these efficiency measures for our sample. We find that Illinois strip mines are fairly efficient (relative to each other). The major source of inefficiency was due to deviations from the optimal scale of production. We also find suggestive evidence that inefficient mines tend to have relatively high stripping ratios, high labor-output ratios, single rather than multiple coal seams, and lower earth-moving capacity.