CM applies the principles of positive reinforcement for performance of desired behaviors consistent with MA abstinence. CM typically involves the contingent delivery of a voucher (which can be traded for desired items or privileges) or other incentives for behaviors, such as attendance at treatment sessions or production of a drug-negative urine specimen. CM has been widely applied to other drug dependence disorders, and a meta-analysis of research findings has documented strong evidence of efficacy across many studies, types of disorders, and populations. Petry (2006) has written on how this technique can be used efficiently and cost-effectively.