Help-wanted advertising dropped in March.

The volume in large papers around the country edged lower in March after nudging higher the previous month, the Conference Board announced. The help-wanted advertising index slipped to 138 from 140 in February and 139 in January, but it was up 12 points from the March, 1983, reading of 124. The seasonally adjusted index, which is sensitive to changes in demand for labor and general business conditions, stood at 100 in 1967. “Want-ad volume in March was not significantly higher than it was five months earlier, and increases in employment over the last four months have only been high enough to keep the unemployment rate from rising,” said Kenneth Goldstein, an economist with the Conference Board.