The national activity index held little changed in negative territory at year-end, at minus 0.51 in December versus minus 0.49 in November. A negative reading for this index doesn't necessarily signal recession, only that growth is under the historical average. Three of the index's four main components contracted in the month with the largest negative coming from production, an echo of trouble being reported in manufacturing.

The Chicago Fed National Activity Index (CFNAI) is a monthly index that tracks overall economic activity and inflationary pressures. The CFNAI is a weighted average of 85 existing monthly indicators of national economic activity. It is constructed to have an average value of zero and a standard deviation of one. Since economic activity tends toward trend growth over time, a positive index reading corresponds to growth above trend and a negative index reading corresponds to growth below trend.

This index is unique among regional Federal Reserve Bank indexes in that it is national in scope. Investors are eager to have insight into economic growth and inflation. This index combines 85 diverse and already released indicators from four broad categories -- production and income; employment, unemployment, and hours; personal consumption and housing; and sales, orders, and inventories -- into an overall index to measure economic performance. The index provides another measure with which investors can measure overall growth.