“…Many studies have evaluated post-intervention effects of CM on substance use months after external reinforcement ceases, but most are underpowered to detect long term changes. Although meta-analyses find effects of CM are not sustained at long term follow-ups (Benishek et al, 2014; Prendergast et al, 2006), an increasing number of studies demonstrate benefits of CM months after treatment ends (Alessi, Hanson, Wieners, & Petry 2007; Carroll et al, 2016; Halpern et al, 2015; Higgins et al, 2000, 2007; Higgins, Heil, & Lussier 2004; Kadden, Litt, Kabela-Cormier, & Petry 2007; Kendzor et al, 2015; McDonell et al, 2013; McKay et al, 2010; Petitjean et al, 2014; Petry, Andrade, Barry, & Byrne 2013c; Petry, Alessi, Byrne, & White 2015b; Petry & Martin 2002; Petry et al, 2005c; Reback et al, 2010; Roll, Chudzynski, Cameron, Howell, & McPherson 2013; Secades-Villa et al, 2011; Secades-Villa, Garcia-Rodriguez, Lopez-Nunez, Alonso-Perez, & Fernandez-Hermida 2014; Schottenfeld, Moore, & Pantalon 2011; Winhusen et al, 2014). A recent review (Davis et al, 2016) reported that 29% of studies that evaluated long-term effects of CM found that it retained significant benefits even after reinforcers were no longer delivered.…”