Thanks to  Jesse Felder , we recently stumbled upon a measure of economic conditions that has reliably signaled every recession since 1948. The data point, Real Value Added, is currently in negative territory and may, therefore, be a harbinger of an economic downturn.  If it is a false signal, it would be the first in a 70-year history of observations.

https://realinvestmentadvice.com/an-indicator-of-peril/