“…Another relevant issue that has not been addressed by the existing spatial frontier frameworks is the potential endogeneity of the inputs, associated with reverse causality or omitted variable bias. 2 Despite its impact on the consistency of the estimators (Amsler, Prokhorov, & Schmidt, 2016), this important concern has been addressed only recently in the SFA literature (Karakaplan & Kutlu, 2017a, 2017bKutlu, 2010;Tran & Tsionas, 2013), while traditional SFA models tend to ignore this potential bias.…”