This paper presents some extremely flexible
identities useful in analyzing changes in unemploy-
ment rates from month to month, from year to year,
and over longer periods. An aggregate unemployment
rate change is expressed as a polynomial in labor
force stocks and first differences in labor force
stocks. Terms of this polynomial are interpreted
as the effects of (1) changes in the distribution
of the labor force among demographic groups; (2)
unexpected changes in labor demand within a demo-
graphic group; and (3) unexpected changes in labor
supply within a demographic group. A simple exten-
sion of the framework shows its relationship to
recent work with labor force gross flow data. The
framework is applied to the increase in black youth
unemployment between 1950 and 1970. Most of it may
be attributed to a decline in employment among male
in the South.