The index was formally introduced in September. It’s an aggregate of 19 other indicators so it’s not a market mover but it’s a nice snapshot of how the Fed might view the labor market.

It came about because the Fed was struggling to explain its view on the labor market as unemployment was falling but other indicators like part-time work for economic reasons and the hiring rate were lackluster.

The prior reading was revised to 3.9 from 4.0.