Single mothers on welfare in San Diego improved their employment and earnings prospects substantially through intensive group "job-search" programs that taught them how to look for jobs, how to behave at interviews and how to contact potential employers, the Manpower Demonstration Research Corp. reported yesterday.

But the program did not work as well for unemployed fathers in two-parent welfare families.

The nonprofit group, monitoring job programs for welfare clients in eight states, said 50 percent of mothers got jobs within a year, compared with 42 percent for a control group not assigned to job search, and their earnings over that year averaged $507 more than the control group.

But the study said the employment rate for fathers -- 63 percent -- was 1 percent less than for the control group, but their earnings were $288 better.

Judith Gueron, MDRC vice president and coauthor of the report, said women probably benefited more from the job-search program than did men because having "less experience in the labor force, they benefit more from assistance in looking for jobs."

The study found that "workfare," requiring welfare recipients to take unpaid community jobs in exchange for their benefits, does not improve employment and earnings prospects much, if at all, for those who have taken job-search classes, although it does provide services to the local community that more than offset the cost of "workfare" progams.

The group based this conclusion on the experience of groups of single mothers and unemployed fathers who were enrolled in intensive job-search activities and a follow-up "workfare" program, in which they got work experience for up to 13 weeks while on welfare.

"The findings should be viewed cautiously," Gueron said, because they involve only one year and because "San Diego may not be typical. It has a strong labor market, it is not industrial, it has more service jobs available than many other areas and its welfare population has more whites, more work experience and more education than many other areas."

The study, which ran from October 1982 to August 1983, involved 7,004 welfare recipients in San Diego who were randomly assigned to participate in job experiments. About half were single mothers. The rest were unemployed fathers in two-parent families.

For the study, 1,887 were assigned to the control group and did not receive job-search or "workfare" services; 1,878 were assigned to job-search services only, and 3,239 were assigned to job-search and "workfare" activities. Only about half those assigned participated.

The study found that among single welfare mothers, 42 percent of the control group got jobs within a year after applying for welfare although most stayed on welfare, too, because their earnings were low; 50 percent of the job-search group got jobs, as did 52 percent of those who participated in both the job-search and "workfare" programs.

Average earnings for the year were $1,392 for the control group, $1,899 for the job-search group, and $1,783 for the final group.

Among the married men, 64 percent of the control group, 63 percent of the job-search group and 66.9 percent of the third group got jobs. Average earnings were $3,602 for the control group, $3,890 for the job-search group and $3,570 for those eligible for job-search and "workfare."

The figures show that program savings from reduced welfare benefits for those who got jobs averaged about $200 a year for single mothers and men in the job-search program and $350 for men who were in the "workfare" program as well.