The existing data envelopment analysis (DEA) models for measuring the relative efficiencies of a
set of decision making units (DMUs) using various inputs to produce various outputs are limited
to crisp data. The notion of fuzziness has been introduced to deal with imprecise data. Fuzzy DEA
models are made more powerful for applications. This paper develops the measure of efficiencies
in input oriented of DMUs by envelopment form in fuzzy production possibility set (FPPS) with
constant return to scale.
