Adjusted spherical frontier model: allocating input via parametric DEA

This paper presents the adjusted spherical frontier model (ASFM), a parametric data envelopment analysis (DEA) model for input allocation. Following a common principle from other solutions found in the literature, ASFM considers that the process of allocating the new input is fair if it ends in such a way that all decision‐making units will become DEA‐CCR efficient. ASFM's main assumption is the spherical shape of the efficiency frontier. It is because of that assumption that ASFM is called a parametric DEA model. Numeric examples are presented showing that, within the context of sensitivity analysis, ASFM reaches more coherent results than other models found in the literature. This numeric evidence leads to a theorem which formally states this more coherent behaviour. The proof of this theorem is included in this paper.