This chapter has four objectives:

1. To justify – Section 1 - the use, in the analysis, of only one DEA model in its plainest and most simple version, when the are a very large number of different Data Envelopment Analysis models and model variants to choose from.
2. To describe how efficiency is measured by the model chosen - the CCR model - and to describe the model itself – Sections 2, 3 and 4,
3. Through a series of simple examples to illustrate how structural properties in the data impact on the measurement of efficiency – Sections 5, 6 and 7, and
4. To identify how measurement of efficiency can be used to identify structural properties in the data such as correlation and dispersion – Section 8.