This is a Methodological Appendix to a paper that explores options for reforming Medicare cost sharing. Using data from the Health and Retirement Study and the Medicare Current Beneficiary Survey, we consider how unified deductibles, alternative coinsurance rates, and a limit on out-of-pocket spending would alter program spending, beneficiary cost sharing, and premiums for supplemental coverage. We show that cost sharing reforms could provide better safeguards to beneficiaries with high costs than the current Medicare benefit structure and that policies could be structured in a way that would add little to overall program costs.