Unemployment rates dropped for the wrong reasons in March. The main U.S. rate ticked down to 7.6%, while a broader rate that includes discouraged workers tumbled 0.5 percentage point to 13.8%.

The drop in the main unemployment rate was driven by a huge drop in the number of people in the labor force. The unemployment rate is based on the number of unemployed — people who are without jobs, who are available to work and who have actively sought work in the prior four weeks. The “actively looking for work” definition is fairly broad, including people who contacted an employer, employment agency, job center or friends; sent out resumes or filled out applications; or answered or placed ads, among other things. The unemployment rate is calculated by dividing the number of unemployed by the total number of people in the labor force.

This month the number of unemployed dropped by nearly 300,000, but it doesn’t appear that most of them found jobs. That’s because the number of employed people also tumbled by more than 200,000. Both numbers dropped because the total number of people working or looking for work tumbled. The labor force participation rate fell to 63.3%, the lowest level since 1979 when women were still just beginning their move into the labor force.