“…In the contemporaneous setting of efficiency analysis, such differences have been empirically observed for value functions (Ang et al,
2018; Kerstens & Van de Woestyne,
2021) and distance functions (Kerstens,
1996). In the intertemporal setting of productivity change, several studies report differences (Ang & Kerstens,
2017; Kerstens et al,
2022,
2018), although there can be special cases of equivalence (Ang et al,
2023). The differences between convex and nonconvex estimates for the components of
remain to be investigated.…”