When the unemployment rate falls below 5 percent, it usually means things are going pretty well. It was 4.7 percent in May, a level last seen in November 2007.

A different measure of the economy’s health, however, is beeping and flashing red. It says that labor market conditions have deteriorated with each passing month this year. In May, it fell to its lowest level in seven years.

Called the Labor Market Conditions Index, it has been billed as a more complete measurement than that old war horse, the unemployment rate. There are two possible explanations for the index’s decline: one somewhat comforting, and the other scary.

Let’s do comfort first. It’s possible we’re not making progress because we’ve more or less arrived at our destination — what economists call full employment. This somewhat misleading term doesn’t mean that everyone has a job. It means that the reservoir of people seeking work has receded to a historically normal level.