Seasonal adjustment is the estimation of the seasonal component and, when applicable, also trading day and moving holiday effects, followed by their removal from the time series. The goal is usually to produce series whose movements are easier to analyze over consecutive time intervals and to compare to the movements of other series in order to detect co-movements.
The U.S. Census Bureau is a world leader in seasonal adjustment research and time series software. These case studies are part of a series to keep data users informed of research and encourage discussion.