Many economic data series have seasonal patterns, which means they tend to occur at the same time each year. Construction employment declines in winter, tourism employment rises in summer, and retail employment peaks in December. Because of such seasonal factors, simply looking at monthly employment statistics may not be enough to reveal true underlying trends. Seasonal adjustment eliminates seasonal fluctuations in monthly employment data, thus permitting comparisons of data from one month to data from any other month. Of the major employment series, only statewide labor force (LAUS) and statewide non-farm employment (CES) data (at the supersector level) are available on a seasonally adjusted basis. Sub-state LAUS and CES data are not seasonally adjusted.
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