... In epidemiological and field studies, workplace performance has been defined by attendance and absenteeism (Bass et al., 1996;French et al., 1998;Van Hasselt et al., 2015), wages (French et al., 1998), employees' perceptions of their work performance (El-Bassel et al., 1997;Lehman and Simpson, 1992), injuries and workplace accidents (Normand et al., 1990), and supervisor ratings (Weiss et al., 2008). Likewise, drug use has been measured using a variety of strategies including self-report (e.g., Lehman and Simpson, 1992;Lim et al., 2000;Roche et al., 2008) and collection of biologically verified samples prior to employment or interview (e.g., Bass et al., 1996;Normand et al., some suggesting drug-related performance impairment (Bass et al., 1996;El-Bassel et al., 1997;Lehman and Simpson, 1992;Normand et al., 1990;Roche et al., 2008;Van Hasselt et al., 2015;Zwerling et al., 1990), and others failing to find a significant relation between drug use and performance (French et al., 1998;Lim et al., 2000;Weiss et al., 2008). ...