A House investigating committee is looking for leads, tips and horror stories relating to the on-going downgrading exercice in government in which thousands of workers are being told, in effect, they are being paid too much.

Hundreds of employees here already have been demoted in rank and pay in recent months and there are more to come. In most cases the workers didn't do anything wrong, but have been set up to be knocked down because audits indicate their jobs don't merit the money and rank they carry. Some of the classification errors go back years.

On Dec. 17, this column reported that "over the next few years at least three of every 10 management workers will be faced with the prospect of a job downgrading that will cost status, career time and money."

That estimate, os a 30 per cent downgrading casualty rate, may in fact be conservative. Some agencies have made preliminary checks that show anywhere from 15 per cent to 40 per cent of their Grade 12 through 15 staffs may be overgraded and overpaid.

President Carter's statements that nobody will be downgraded, demoted or hurt because of the government re-organization he's planning will be hard to live up to. In fact, they could push agency managers into quickie downgrading studies and actions, so that all the damage is done before the reorganizations take place, therefore leaving the President's promise intact.

Chairman Robert N.C. Nix (D-pa), new boss of the House Post Office Civil Service Committee, is worried about the methods being used in some downgradings. He also is concerned about rumors that some agencies are operating a "quota" system whereby a certain number of jobs must go under the knife regardless of the justification for downgradings.

He has assigned his Investigations Subcommittee staff director Tom Kennedy to find out what is going on.

To do that, the subcommittee needs to hear from employees who have been caught up in - or are facing - demotion actions.

Nix's Investigations subcommittee is zeroing in, for moment, on Health, Education and Welfare, which has 36,000 employee here.HEW has been pushing job audits, especially in the Office of Education and Social and Rehabitation Service. The subcommittee also is interested in Commerce. Interior and Defense where tight lids have been placed on top of jobs and bothArmy and Navy have taken steps to reduce the number of Grade 12 through 15 workers over the next couple of years.

The subcommittee also is looking for evidence that holdovers from the Ford Administration managed to finesse career jobs for themselves and friends at high grades, even as downgradings are taking place in their agencies.

Anyonw with tips on the downgrading situation should contact Tom Kenney at the subcommittee, Room B-370, Rayburn House Office Building.