In evaluating CBT4CBT, we adhered to the Stage Model by first testing it in small randomized pilot studies, emphasizing internal validity and mechanism at Stage 1, before conducting larger studies with fewer experimental controls (Rounsaville et al., 2001). As such, we attempted to avoid some of the methodological problems common to some studies of web-based interventions, such as weak controls (e.g., wait lists), lack of attention to treatment adherence and fidelity, reliance on unvalidated self-reports of change, low rates of follow-up and others (Kiluk, Sugarman, et al., 2011). The first pilot study randomized 77 substance users to either standard outpatient treatment at a community setting or standard treatment plus access to CBT4CBT for 8 weeks. This approach allowed monitoring of participants use of the program, verification of self-reports of drug use via biological markers, and a relatively strong comparison condition (treatment as usual, TAU). This trial demonstrated significant differences in drug free urines by condition (Carroll, Ball, Martino, Nich, Babuscio, Nuro, et al., 2008) as well as continuing improvement for those assigned to CBT4CBT through a 6-month follow-up (Carroll, Ball,
