AFTER ALL THE high-level, hurry-up help that went into Mayor Barry's ambitious effort to find summer jobs for the youth of this city, the program is in a shambles. On-the-spot checks around town have turned up widespread confusion, fouled-up assignments, no-shows, bureaucratic disputes and serious payroll erros, Worse, the mayor's man in charge of it all, Acting D.C. Labor Department Director Matthew Shannon, claims he's unawae of any major problems.

No expected the summer-job effort to come off without a hitch, since it was an exceptional crash program. Mayor Barry was determined to double the number of jobs available this summer, from 15,000 to 30,000 -- and he claimed to have made his goal. He was helped considerably by extraordinary efforts on the part of the Metropolitan Washington Board of Trade other businessmen and federal agencies, as well as by the chairmen of congressional appropriations subcommittes, Sen. Patrick J. Leahy (D-Vt.) and Rep. Charles Wilson (D-Tex.). In addition, sensitive aides in the mayor's office of youth affairs saw to it that the start of the jobs progam was staggered, so that possible payroll problems could be averted.

No soap. At some city projects, only half as many teen-agers as promised were assigned; at others far too may were dispatched. At every job site surveryed employers and teen-agers reported that biweekly checks were not arriving on time or were made out for the wrong amounts. Says Mr. Shannon: "There are times when I don't get a paycheck because of some mess-up. But that's no reason to stop working or condemn the Department of Labor." But to kids who have spent money on food and transportation -- and whose perception of the workplace can be neddlessly warped by sloppy management -- it sets a terrible example. And to empolyers who have committed time, money and significant numbers of promising jobs to the mayor's effort, it is a discouraging snub.

Mayor Barry's personal campaign to increase the number of summer jobs for youth was -- and still is -- an enormously important project that will be just as important next next year at this time. If the city expects the same sympathetic, vigorous response from Congress and private industry, the mayor had better take whatever administrative steps are necessary to jolt his Labor Department into proper action.