Hawaii Medical Service Association is on the verge of making a historic change in how it reimburses primary care medical providers. Until now the largest private payer in the state has reimbursed physicians on a fee-for-service basis. Under its Payment Transformation Pilot, HMSA will instead pay selected providers a fixed dollar amount for each member in their practice each month. HMSA believes that this will benefit patients, providers and the insurer because it will improve clinical outcomes and contain costs. Will it work? That remains to be seen.