In a recent study [55], clients earned reinforcers for attending clinician-led group counseling sessions and/or the in-clinic patient-led Methadone Anonymous (MA) groups. This non-research, clinical effort addressed historically poor therapy attendance at the clinic, and attendance rates were compared before, during, and after the CM program. CM increased attendance to both groups in the short-term after implementation, but effects were more robust for the MA groups in which increased attendance persisted 3 months following the withdrawal of the contingencies. Overall effects of this program were modest, but they are notable given the use of an ultra-low cost approach.
Delivery Methods
The majority of CM studies used voucher or prize-based methods. Head-to-head comparisons suggest that they are comparable in efficacy [63–65], and each has advantages and disadvantages that may make one option more appealing for a given clinic. Voucher programs are generally straightforward to administer. Clients earn vouchers for each instance of the target behavior. The value of the vouchers typically increases with consecutive performance. The schedule used in the influential Higgins et al studies [66,67] started at $2.50 for the first cocaine-negative sample and increased by $0.50 for each subsequent consecutive cocaine-negative sample. Earned vouchers are exchanged for goods or services selected by the client, increasing the likelihood that the selected items will be highly desirable and allowing for a wide range of client preferences. Clients appear to prefer this approach when given a choice between set schedules or those that introduce an element of chance (ie, prize-based CM, discussed below) [68]. However, voucher programs can be costly (~$1000 per client over 12 weeks) and may require more staff time to fulfill individual requests for specific items. However, staff burden related to shopping can be reduced by limiting these individual requests and using an on-site stocked cabinet of goods similar to prize-CM programs.
Prize-based CM is similar but introduces probabilistic earnings and variability in prize magnitude. Rather than earning vouchers, clients earn draws from a fishbowl for each instance of the target behavior, again typically in an escalating manner. For example, a client may earn one draw from the fishbowl for the first cocaine-negative sample, 2 draws for the second consecutive negative sample, 3 draws for the third, and so on. A typical fishbowl is composed of 500 slips, some noting prizes and some having no prize value. Typically, half the slips in the bowl are non-monetary “good jobs.” The remaining half are small prizes worth about $1 in value (eg, food coupons, bus tokens, small toiletries), large prizes worth about $20 in value (eg, small electronics, gift certificates), and one slip is the jumbo prize worth about $100. When a client draws a winning slip, they select a prize from that category (ie, small, large, jumbo) from an onsite, stocked cabinet. Due to the probabilistic feature of prize-based CM, overall costs of the program can be substantially lower than typical voucher programs, with average maximum expected earnings ranging $250 t $450 per client over a 12-week treatment period [15,16,65,69]. Advantages of this method include potentially lower costs and minimal shopping demands (a once-monthly shopping trip to restock the cabinet will usually suffice) while maintaining comparable efficacy. Relative to voucher programs, prize-based CM involves additional administration time to allow for drawing slips from the fishbowl, which can be compounded when multiple clients want to draw at the same time such as in a group setting. Many of the group-based CM adaptations address this issue by limiting the number of clients who can draw for prizes in a given group or by limiting the number of draws per client [25,27,54].
Reinforcers
Regardless of whether selecting voucher or prize CM, reinforcers are critically important to the success of the program. Reinforcers must be desirable. One of the quickest ways to undermine a CM program is lack of variety or undesirable reinforcers. If stocking a cabinet with prizes onsite, care should be taken to have numerous options within each of the small and large prize categories that are appealing to a wide range of clients. Since a client who is consistently earning draws will choose prizes often, it is imperative to include enough variety so that even these clients find desirable items each time they select a prize. Clients should be asked regularly if they have suggestions for prizes; one program [54] found suggestion boxes useful for encouraging clients to voice their preferences. Donations can be solicited from local businesses to reduce costs [53], and low-cost but high-value options, such as clinic privileges, can also be explored. Petry [1,44] provides some suggestions of the latter, and Amass and Kamien [70] describe their successful strategies to fund and sustain a clinic-based CM program through community donations. Some clinics may already have tangible goods, such as gas or metro cards, that are offered to clients based on need rather than behavior [53]. These existing resources might be redirected to a CM program, in which these goods are contingent on abstinence or attendance, if appropriate.
Schedule Parameters
Once the target behavior, client population, and CM delivery methods are selected, the next step is to design the reinforcement schedule. The following schedule parameters apply to both voucher and prize-based CM systems. The more closely a clinical program adheres to the parameters of effective protocols, the more likely the program is to generate comparable outcomes. If there is a parameter or design feature that is incompatible with clinic needs, modifications can be introduced. However, each deviation away from the ideal has a chance of undermining the success of the CM program. Any changes and their potential impacts should considered carefully, and consultation with a CM expert may aid in the development of successful and efficacious clinic-based protocols. Of note, a meta-analysis [13] of CM studies found that researcher involvement in the planning and design of CM programs is associated with larger treatment effects. CM researchers are especially attuned to the potential impacts and pitfalls associated with modifying CM protocols, and they can be valuable resources for clinics interested in tailoring a CM program to their specific needs. Several examples of clinical demonstration projects that used researcher input are available [19,53,71].
Magnitude
Incentive magnitude was directly related to the size of treatment effects in a meta-analysis [11] of CM studies. Although not all studies find significant differences in outcomes related to magnitude [65,72], the bulk of evidence suggests magnitude is an important parameter and is related to effect size for both voucher [73–75] and prize-based CM [69,76] systems. Thus, although clinics may have restrictive budgets, severely undercutting the magnitude of rewards is not usually the solution as it can undermine treatment effects [76]. Donations can reduce overall costs [53,57,70], and other protocol features discussed below, such as capping the amount of reinforcement available, can reduce the overall magnitude available per patient.
