A friend used to work for Korn Ferry, a publicly-traded headhunting firm. She said that their stock was a leading indicator of economic trends because firms halt executive recruiting efforts as they can see warning signs for their business. This happens before the clients issue quarterly revenue guidance that makes their expectations explicit.
I almost used the more PC term, 'executive recruiting'. But many/most people I know refer to them as 'headhunters'. At least some in the industry object to this term, but it is still widely used by people at large.
When I was young, I thought headhunter was the coolest job title ever. Now my wife is a recruiter, and I think of her as a headhunter. My mental picture of her day is a lot more violent than reality.
Every answer you will get in this thread is wrong because once something becomes well known enough to be tracked, it stops being a “naive indicator”
The warden buffet underwear thing being a prime example. Every Walmart merchandiser now knows that “rule of thumb” and prices underwear against that “common knowledge”
Consumer goods prices swinging low relative to inputs, profit ratios falling, or price and quantity moving in ways to suggest weaker demand, should all be determinable with some degree of confidence.
That requires richer data than strictly following sales volumes, of course.
But the basic principle is still one of supply and demand, and following both shifts. The ability of retailers to adjust prices in near-real-time to demand shifts changes the behaviour somewhat. It doesn't demolish the concept of market function.