underemployment
Some people have a job, and the statistics happily count them as 'employed' — yet they are wasted. A trained engineer driving a taxi because no engineering jobs are open; a worker who wants 40 hours a week but can only get 15; a graduate stacking shelves while their degree gathers dust. They are not unemployed, because they do have work. But they are not fully used either. This in-between state is underemployment.
Underemployment comes in two main forms. The first is hours-based: people who are working part-time but would prefer full-time hours and cannot get them — often called involuntary part-time work. The second is skills-based: people working in jobs far below their qualifications or abilities, so their training and talent are underused. In both cases the person is officially employed and so does not show up in the unemployment rate at all, even though there is real slack — unused capacity to work — sitting inside their situation.
Underemployment matters because the standard unemployment rate can look healthy while a large share of the workforce is quietly under-used, dragging down incomes, productivity, and morale. It is one of the main things broad measures of labour-market slack (such as the U-6 rate) try to capture by adding involuntary part-timers to the count. The catch is that underemployment, especially the skills-based kind, is genuinely hard to measure — there is no clean line between a job that fits you and one that under-uses you — so figures should be read as indicative rather than exact.
After the downturn, Maria finds only a 12-hour-a-week shop job, though she wants and needs full-time work, and her former colleague Raj, an architect, is delivering food because no design firms are hiring. Both are counted as 'employed', yet both are underemployed — their full capacity to work is going unused.
Underemployment is slack hiding inside the 'employed' count — too few hours, or skills going to waste.
Underemployment is not unemployment: these people have jobs, so they don't show up in the standard rate. That is exactly why a low unemployment rate can still sit beside a lot of wasted labour.