The Chicago Fed National Activity Index (CFNAI) is designed to gauge overall economic activity and related inflationary pressure. The CFNAI is based on a weighted average of 85 existing monthly indicators of national economic activity. It has an average value of zero and a standard deviation of one. Since economic activity tends toward trend growth rate over time, a positive reading corresponds to growth above trend and a negative reading corresponds to growth below trend.
A higher than expected figure should be seen as positive (bullish) for the USD while a lower than expected figure should be seen as negative (bearish) for the USD.