Each living cell needs to solve a resource allocation problem, in which multiple inputs (uptake fluxes) and outputs (secretion fluxes) are the outcome of the stoichiometry of biochemical pathways and the regulation of metabolic enzymes. Quantifying the efficiency with which a cell solves this resource allocation problem constitutes a basic question in "cellular economics". In this letter, we propose the use of data envelopment analysis (DEA) to define multidimensional yields that can capture the multidimensional nature of cell input-output processes. The DEA, by treating cells as decision-making units, enables one to introduce the concept of efficiency frontier that is both intimately connected to the shadow prices of flux balance analysis and useful to estimate the phenotypic phase space from experimental measurements of fluxes.
