"Index shows economic growth decreased in January." This is the headline for today's release of the Chicago Fed's National Activity Index, and here are the opening paragraphs from the report:

Led by declines in production-related indicators, the Chicago Fed National Activity Index (CFNAI) decreased to –0.05 in January from +0.18 in December. Three of the four broad categories of indicators that make up the index decreased from December, and two of the four categories made negative contributions to the index in January. [Link to News Release]

The previous month's CFNAI was revised upward from 0.14 to 0.18. November was also revised upward.

Background on the CFNAI

The Chicago Fed's National Activity Index (CFNAI) is a monthly indicator designed to gauge overall economic activity and related inflationary pressure. It is a composite of 85 monthly indicators as explained in this background PDF file on the Chicago Fed's website. The index is constructed so a zero value for the index indicates that the national economy is expanding at its historical trend rate of growth. Negative values indicate below-average growth, and positive values indicate above-average growth.

The first chart below shows the recent behavior of the index since 2007. The red dots show the indicator itself, which is quite noisy, together with the 3-month moving average (CFNAI-MA3), which is more useful as an indicator of the actual trend for coincident economic activity.

CFNAI since 2000

For a broad historical context, here is the complete CFNAI historical series dating from March 1967.

CFNAI

The next chart highlights the -0.7 level. The Chicago Fed explains:

When the CFNAI-MA3 value moves below -0.70 following a period of economic expansion, there is an increasing likelihood that a recession has begun. Conversely, when the CFNAI-MA3 value moves above -0.70 following a period of economic contraction, there is an increasing likelihood that a recession has ended.