The Office of Personnel Management is starting a study of about 114,000 federal jobs exempted from competitive civil service exams, with an eye to weeding out some of those exemptions.

But the OPM concedes that the hoe will not reach many of the positions exempted under Schedule A (positions for which no examination is practical) and Schedule B (jobs for which competitive exams don't make sense). "A good chunk" of the Schedule A positions, for instance, are held by lawyers, an OPM official said, and attorneys are protected by statute from examination. Neither are the exemptions enjoyed by chaplains in any danger, because of constitutional protections. Schedule B exemptions for students in cooperative education programs will stay, too, because the schools pick those jobholders, not the government.

So who's left? Well, there are a few jobs at the GS4 level and below held by mentally retarded persons who have been deemed unexaminable. And then there are the temporary, part-time or intermittent jobs.

Meanwhile, the OPM has started a crackdown of sorts on Schedule C jobs, the ones held by political and patronage appointees. The authority for deciding whether a position is covered by a Schedule C exemption--delegated to agencies in the Carter administration--has come back to OPM under the Reagan administration.

There are 1,239 Schedule C jobs that are filled now, fewer than the 1,509 filled when the Carter administration left office. But both OPM and the White House say there was never any intent to pare the size of government by going after the Schedule Cs.