“…The identification of all the possible reference DMUs for an inefficient unit is an important and interesting problem in DEA, on which we concentrate in this contribution by means of the non-radial range-adjusted model (RAM) of Cooper, Park, and Pastor (1999). This issue has received significant attention in the literature due to its wide range of potential applications in ranking (Jahanshahloo, Junior, Hosseinzadeh Lotfi, & Akbarian, 2007), benchmarking and target setting (Bergendahl, 1998;Camanho & Dyson, 1999), and measuring returns to scale (RTS) (Cooper, Seiford, & Tone, 2007;Krivonozhko, Førsund, & Lychev, 2014;Sueyoshi & Sekitani, 2007a;Sueyoshi & Sekitani, 2007b;Tone, 1996;Tone, 2005;Tone & Sahoo, 2006).…”