Federal workers and retirees who complain about the conservative investment habits of their pension fund should be delighted, after this week, that their fund, unlike those of some state and local governments, doesn't play the stock market.

The federal retirement program is the nation's largest "company" plan covering 5 million workers, retirees and spouses. It pays benefits to a variety of former federal workers including several ex-presidents, senators and House members and a substantial number of civil servants who retired in the 1940s before most of the current work force was born.

The federal system bases benefits on length of service and salary. It promises them and their survivors benefits they cannot outlive that are linked to the cost of living.

Under the federal pension program employes must contribute 7 percent of salary during their working careers, whereas most private pension plans require little or no employe contribution. But because of their own investment -- and because the pension plan also covers members of Congress -- the federal retirement system typically pays a better benefit.

Workers who retire at age 55 with 30 years of service, for example, get a starting benefit equal to just over 56 percent of their highest three-year average salary. A worker who has 41 or more years of service gets an 80 percent benefit. Many private plans penalize workers who retire before age 62, and many base the benefit on the employe's highest five-year average salary, although some offer stock options or other benefits.

Federal workers who complain about the system often say the funds would get a better return if they invested in stocks, rather than guaranteed government securities.

Many pension plans -- private as well as local and state governments -- invest in higher yield stocks, which, we all learned this week, can be riskier.

This week there have been true horror stories of government and private pension plans losing billions of dollars because of the market slide. Fairfax County, for example, in one day lost 20 percent of the paper value of its pension fund. On the other hand Maryland fared better because earlier this month it moved $2 billion of state pension fund money out of stock market investments.

Many experts hope and expect the market will recover. But right now Uncle Sam's investing habits look very good.Retirement Switch

Dec. 31 is the deadline for federal workers who must choose between the old Civil Service Retirement System and the new Federal Employees Retirement System. At 1 p.m. tomorrow on WNTR radio (1050 AM) Allison Summerton, a pension expert with Chambers Associates, will talk about the options facing federal workers and answer questions from people who are trying to decide their pension future.Hatch Act

The bill to amend the Hatch "no politics" Act wound up with a healthy 292 cosponsors when it was reported out of the House Post Office-Civil Service Committee last week. That is a good sign for advocates of greater partisan political freedom for federal workers because it takes 290 votes to guarantee a House override of a presidential veto.

Meanwhile, federal and postal unions are trying to get more House members to sign on to the legislation in an effort to convince the White House that the bill can't be stopped, and to get the Senate moving on the proposal.