Returns to scale and scale elasticity in Farrell, Russell and additive models

This research extends the Farrell-based returns to scale methodology into Russell and Additive models in three ways with the focus of relationships between interior points and projected points. First, we present and prove four theorems that identify the scale nature. Second, we compare these results with the scale elasticity results. Third, we present techniques for estimating upper and lower bounds for the scale elasticities.