The leaders of Colorados Public Employee Retirement Association (PERA) assure us that if we have patience, long-term investment returns of 7.5 percent will fully fund the programs promises to retirees over the next 40 years or so. But what if those returns fail to materialize? Moving PERA from the current defined benefit plan to a defined contribution or cash balance-style plan would remove much of the burden of returns falling short from taxpayers, while helping along the long-term financial health of PERA.