Importance for DEA of zeros in data,multipliers, and solutions

Some prominent literature in the DEA field has displayed the following three problems involving zeros: (1) The structural role of zeros in data has not necessarily been recognized; in fact, without explanation, arbitrary, small positive numbers have been substituted for such zeros. (2) It is not well recognized that the artificial, non-Archimedean construct is not necessarily needed to exclude zero multipliers and to identify positive slacks. (3) Because of degeneracy, optimal solutions are not necessarily unique; this lack of uniqueness is especially important in interpretation of the multipliers and slacks.The editor for this paper was R. Robert Russell.