Data Envelopment Analysis
Data Envelopment Analysis DEA is an increasingly popular management tool. This write-up is an introduction to Data Envelopment Analysis DEA for people unfamiliar with the technique.
For a more in-depth discussion of DEA, the interested reader is referred to Seiford and Thrall 1990 or the seminal work by Charnes, Cooper, and Rhodes 1978 .
DEA is commonly used to evaluate the e ciency of a number of producers. A typical statistical approach is characterized as a central tendency approach and it evaluates producers relative to an average producer In contrast, DEA compares each producer with only the "best" producers. By the way, in the DEA literature, a producer is usually referred to as a decision making unit or DMU.
DEA is not always the right tool for a problem but is appropriate in certain cases. See Strengths and Limitations of DEA.
In DEA, there are a number of producers. The production process for each producer is to take a set of inputs and produce a set of outputs. Each producer has a varying level of inputs and gives a varying level of outputs. For instance, consider a set of banks. Each bank has a certain number of tellers, a certain square footage of space, and a certain number of managers the inputs. There are a number of measures of the output of a bank, including number of checks cashed, number of loan applications processed, and so on the outputs. DEA attempts to determine which of the banks are most e cient, and to point out speci c ine ciencies of the other banks.
A fundamental assumption behind this method is that if a given producer, A, is capable of producing YA units of output with XA inputs, then other producers should also be able to do the same if they were to operate e ciently. Similarly, if producer B is capable of producing
YB units of output with XB inputs, then other producers should also be capable of the same production schedule. Producers A, B, and others
References: A good source covering the eld of productivity analysis is The Measurement of Productive E ciency edited by Fried, Lovell, and Schmidt, 1993, from Oxford University Press