The Massachusetts pension system, which covers state workers and teachers, received a failing grade in a new study on public pensions issued by the Urban Institute, a Washington-based nonprofit research group. The findings come out of a nationwide study of 660 different pension plans in all 50 states.

To be fair on a couple of things: First, no state got an overall A rating; 11 got overall B ratings and the vast majority, 35, got overall C ratings. Four states, including Connecticut and Rhode Island, got overall D ratings. Drilling down to subset levels, 11 percent of all of the 660 plans in the study received failing grades, so Massachusetts is hardly alone. Only 1 percent of the plans studied got an A grade.

Second, the study didn’t take into account some corrective measures to which Massachusetts has recently committed, most notably an agreement by the Patrick administration and legislative leaders to increase funding for the state pension plan for the next three years and beyond, with a target of fully covering retirement obligations by 2036. (Granted, the further out the outlook, the less probable the predicted outcome.)

Another problematic issue of the Massachusetts pension system is vesting time. Massachusetts’ plan requires 10 years of service before employees become eligible for investment benefits of the pension system. Until then, employees, who put 9 to 11 percent of their earnings into the plan, might as well be putting that money into CDs in a bank (the upside is that they wouldn’t have lost money if the stock market declined). This disincentive for early investment goes against the most basic of investment advice; specifically, that early contributions are the best asset-builders over time, and younger workers have more time to recover from market downturns than those closer to retirement.

The long vesting wait is regarded on one hand as fiscally prudent, and on the other hand as out of step with today’s workforce. Private-sector employers can offer much quicker vesting opportunities to young workers, as well as portable 401(k) plans. But slapping a 401(k) plan on top of the existing state system would create the problem of how to support the defined-benefit pensions of older workers, because contributions from younger workers now shore up the pensions of older ones. Massachusetts is far from the only state to face this dilemma.

Then, there’s no incentive for older workers to work longer if they can collect full benefits at the stated retirement age. The term “Old and In the Way,” dating from generations past, goes far beyond political incorrectness. We need to retain experienced older workers due to the existence of legacy data systems, as well as the dearth of younger workers who can step in at the same skill-set capacity.

The study recommends cash-balance plans and other alternative benefit designs, to enable state and local government employees to accumulate retirement savings gradually, including those with short careers, rather than restricting benefits to those with the longest tenures. Massachusetts, and many other states, must find a way to level the playing field between the generations in order to promote sustainability and fiscal harmony.