The official definition of Unemployed as used in the
U-3 is
People are classified as unemployed if they meet all of the following
criteria: They had no employment during the reference week; they were
available for work at that time; and they made specific efforts to find
employment sometime during the 4-week period ending with the reference
week. Persons laid off from a job and expecting recall need not be
looking for work to be counted as unemployed. The unemployment data
derived from the household survey in no way depend upon the eligibility
for or receipt of unemployment insurance benefits.
The alternative measures of labor underutilization are
U-1 Persons unemployed 15 weeks or longer, as a percent of the civilian labor force
U-2 Job losers and persons who completed temporary jobs, as a percent of the civilian labor force
U-3 Total unemployed, as a percent of the civilian labor force (official unemployment rate)
U-4 Total unemployed plus discouraged workers, as a percent of the civilian labor force plus discouraged workers
U-5 Total unemployed, plus discouraged workers, plus all other marginally attached workers, as a percent of the civilian labor force plus all marginally attached workers
U-6 Total unemployed, plus discouraged workers, plus all marginally attached workers, plus total employed part time for economic reasons, as a percent of the civilian labor force plus all marginally attached workers
Discouraged: Did not work during the reference week or look for work in the previous 4 weeks but did look in the previous 12 months, wants to work, is available to work and did not look because of belief in inability to find work. Includes believes no work available, could not find work, lacks necessary schooling or training, employer thinks too young or old, and other types of
discrimination
Marginally attached: Did not work during the reference week or look for work in the previous 4 weeks but did look in the previous 12 months, wants to work, is available to work and did not look for reasons other than discouragement (in school or training, child care or transportation issues, illness, disability, etc)
Part time for economic reasons: Wants to work full time but worked part time (<35 hrs/week) ror economic reasons. Economic reasons include slack work or unfavorable business conditions, inability to find full-time work, and seasonal declines in demand.due to slack business, cut hours, or couldn't find full time work
Definitions are derived from
Employment and Earnings