“…While radial models assume that input reductions and output expansions change proportionally (Seiford & Zhu, 1999;Lewis & Sexton, 2004;Castelli, Pesenti, & Ukovich, 2010;Yang & Liu, 2012;Kao, Wu, & Huang, 2017;Marchetti & Wanke, 2017), non-radial models are a more flexible evaluation tool that can compute input contractions and output improvements individually (Yu & Lin, 2008;Barros, Managi, & Matousek, 2012;Xu & Cui, 2017). Furthermore, given that slacks have been recognized as important factors in explaining inefficient behavior (Mahlberg & Sahoo, 2011), a network slacks-based measure (NSBM) model proposed by Tone and Tsutsui (2009) has been widely used for performance evaluation in various industries (Avkiran, 2009;Yu, 2010;Galagedera, Watson, Premachandra, & Chen, 2016;Zha, Liang, Wu, & Bian, 2016;Xu & Cui, 2017).…”