OBJECTIVES: - Assess the methodological challenges of evaluating appropriate willingness to pay thresholds (WTP) in cost-effectiveness studies which do not use a societal perspective or a QALY outcome measure. METHODS: –Tailored Activity Program (TAP), an intervention designed to reduce caregiver burden for dementia patients, served as a case study.  Caregiver interventions such as TAP employ an individual perspective and non-QALY outcome measures such that standard societal WTP thresholds are not applicable. Two outcome measures related to caregiver burden were used 1) reduction in hours “on duty,” and 2) reduction in hours “doing things.”  To estimate appropriate WTP values for each TAP outcome measure, we identified three studies which met these inclusion criteria:  1) published studies in the past 5 years using contingent valuation methodology to identify WTP, 2) assessed WTP for a dementia-related intervention that required an out-of-pocket expenditure, and 3) asked caregivers what they would be willing to pay for an outcome of reducing caregiver burden.  We also assessed WTP based on the potential financial savings caregivers could achieve from purchasing TAP. To assess proportion of time TAP was cost-effective, we built a Monte Carlo simulation to test the four WTP values identified. RESULTS: – For the outcome measure “on duty” WTP varied between $1.06/hr-$4.58/hr.  WTP for the outcome measure “doing things” varied between $2.21/hr-$9.57/hr.  Applying WTP values to TAP indicates TAP cost-effectiveness varies between 50%-80% for both outcome measures. CONCLUSIONS: – If WTP data can not be collected prospectively or societal values can not be applied, evaluating WTP using comparable studies appears to be an acceptable method for informing decisions makers of potential cost-effectiveness.  Application of WTP to TAP shows potential cost-effectiveness that can be expected under different WTP scenarios.