“…Researchers proposed different perspectives and used different DEA models such as the CCR model (Charnes, Cooper and Rhodes, 1978), which is used to measure technical efficiency under the assumption of constant return to scale (CRS) (Nasierowski and Arcelus, 2003; Hollanders and Celikel-Esser, 2007; Fritsch and Slavtchev, 2011; Chen et al , 2018; Zabala-Iturriagagoitia et al , 2021), BCC model (Banker, Charnes and Cooper, 1984), which is used to measure pure technical efficiency assuming variable return to scale (VRS) (Zhang and Wang, 2019), CRS and VRS models together (Sharma and Thomas, 2008; Afzal, 2014), two-stage DEA model (Carayannis et al , 2016), network DEA model (Alnafrah, 2021; Chen and Guan, 2012; Choi and Zo, 2019; Guan and Chen, 2012; Guan and Zuo, 2014; Kaihua and Mingting, 2014; Kou et al , 2016), dynamic DEA (Chen et al , 2018), global Malmquist productivity index (Zabala-Iturriagagoitia et al , 2021) and fuzzy-set qualitative comparative analysis DEA (Prokop et al , 2021). Barbero et al (2021) estimated national innovation efficiency by frontier DEA-TOPSIS method. In addition to DEA, stochastic frontier analysis (SFA) is also used in some studies (Bai and Li, 2011; Fritsch and Slavtchev, 2011).…”