U-3 vs. U-6 Unemployment: What's the Difference?
The Two Headline Definitions
U-3 is the official unemployment rate — the one quoted in the monthly jobs report and in every news bulletin. It counts people who have no job, are currently available for work, and have actively looked for work at some point in the previous four weeks, expressed as a percentage of the civilian labor force. U-6 is the broadest of the BLS's six alternative measures. It takes everyone in U-3 and adds all marginally attached workers plus everyone employed part time for economic reasons, expressing the total as a percentage of the labor force plus the marginally attached. Both come from the same Current Population Survey interviews; the difference is entirely in who counts.
The Two Groups U-6 Adds
Marginally attached workers are people who want a job and are available for work and have looked for work sometime in the past twelve months, but not in the last four weeks — so they fall outside the labor force under the U-3 definition. Discouraged workers are the subset of that group who give a job-market-related reason for having stopped looking, such as believing no work is available or that employers would reject them. The second addition is workers employed part time for economic reasons, sometimes called involuntary part-time workers: people who want and are available for full-time work but are working fewer hours because their hours were cut or they could only find part-time work. Under U-3 these people are simply counted as employed.
The Full Ladder: U-1 Through U-6
- U-1: Persons unemployed 15 weeks or longer, as a percent of the labor force — the narrowest measure, focused on long-term joblessness.
- U-2: Job losers and persons who completed temporary jobs, as a percent of the labor force — it excludes voluntary quitters and new entrants.
- U-3: Total unemployed as a percent of the civilian labor force — the official rate.
- U-4: U-3 plus discouraged workers, with those workers added to the labor force denominator.
- U-5: U-4 plus all other marginally attached workers.
- U-6: U-5 plus all persons employed part time for economic reasons — the broadest measure.
Each rung is a superset of the one before, so the measures rise monotonically from U-1 to U-6 only in the sense that U-3 through U-6 nest; U-1 and U-2 are narrower slices rather than steps on the same ladder.
How to Read the Gap Between Them
U-6 is always higher than U-3, typically by several percentage points, because it counts groups that U-3 excludes by construction. What matters analytically is not the level of the gap but its width over time. A gap that widens while U-3 falls suggests that improvement in the headline number is being flattered by discouragement or by involuntary part-time work — the labor market is looser than the official rate implies. A narrowing gap suggests genuine tightening, with part-time workers moving to full-time hours and people on the margins re-entering active search. Neither measure is the correct one in isolation. U-3 is the internationally comparable standard and has the longest consistent history; U-6 captures underemployment that U-3 cannot see. Serious analysis reads them together, alongside the participation rate and the employment-population ratio.