Calculating Cost Efficiency with Integer Data in the Absence of Convexity

One of the new topics in DEA is the data with integer values. In DEA classic models, it is assumed that input and output variables have real values. However, in many cases, some inputs or outputs can have integer values. Measuring cost efficiency is another method to evaluate the performance and assess the capabilities of a single decisionmaking unit for manufacturing current products at a minimum cost with its input prices. In this paper, we proposed a model which is capable of calculating the cost efficiency in the absence of convexity when some of the input parameters have integer values, and then we implemented the mentioned model with a numerical example and discussed the results.