In its deliberations, the committee relied on a number of monthly and quarterly economic indicators published by government agencies.The Appendix to this announcement lists these indicators and their sources. The peak marks the end of the expansion that began in November 2001 and the beginning of a recession.
Third, the government does not publish a price index corresponding to the coverage of the measure.
The committee uses the same interpolated GDP deflator as discussed above.
Because this deflator is only available quarterly, the committee interpolates the published series to approximate a monthly price index for GDP.
The resulting monthly measure of real personal income less transfers is an imperfect measure of monthly real output because of definitional differences between personal income less transfers and gross national income and because we use the interpolated price index.
Between trough and peak, the economy is in an expansion.
Because a recession is a broad contraction of the economy, not confined to one sector, the committee emphasizes economy-wide measures of economic activity.Payroll employment, the number of filled jobs in the economy based on the Bureau of Labor Statistics' large survey of employers, reached a peak in December 2007 and has declined in every month since then.An alternative measure of employment, measured by the BLS's household survey, reached a peak in November 2007, declined early in 2008, expanded temporarily in April to a level below its November 2007 peak, and has declined in every month since April 2008.The Appendix also describes the calculations required to reproduce the series that the NBER committee examined in its deliberations.The committee identified December 2007 as the peak month, after determining that the subsequent decline in economic activity was large enough to qualify as a recession.The product-side estimates fell slightly in 2007Q4, rose slightly in 2008Q1, rose again in 2008Q2, and fell slightly in 2008Q3.