“…To separate them, the empirical studies have been assuming asymmetric distribution to the efficiencies (usually a half-normal), while they used to assume that random errors follow a symmetric distribution (usually the standard normal) (Aigner et al , 1977). Even though the SFA is traditionally parametric, the latter improvements have given it some degrees of convergence with non-parametric models, which are referred as the non-parametric or semiparametric SFA (Banker and Maindiratta, 1992; Fan et al , 1996; Kneip and Simar, 1996; Kumbhakar et al , 2017; Kuosmanen and Kortelainen, 2012; Noh, 2014; Parmeter and Racine, 2013). Essentially, Fan et al (1996) and Kneip and Simar (1996) provided the baseline studies for these methodologies.…”