Maryland officials decided not to lower their expectations for the state’s returns on its pension investments, even though economists say the projections are unrealistically rosy.

The Board of Trustees for the Maryland State Retirement and Pension System, which pays for state employee retirement benefits, has set its expected investment return at 7.75 percent, nearly twice the system’s average annual return between 2000 and 2010, and much higher than the 5.5 percent rate that Moody’s Investors Service is projecting for pension funds nationwide.