Best change

A procedure for incorporating newly available source data so thatthe estimates provide accurate measures of change across time periods, though the levels of the estimates may not be consistent with the newer source data. Because, in general, the levels of economic time series are only revised as part of an annual or a comprehensive update, newly available source data are frequently incorporated into the current quarterly estimates on a best-change basis in order to avoid discontinuities in the time series. In general, the best-change procedure is carried out by applying quarter-to-quarter growth rates from the source data to a previously published estimate for an earlierperiod.