lipstick indicator
n. The tendency for lipstick sales to increase prior to and during a recession.
Examples
2003
You're not imagining it: Shopping can contribute to your psychological health in times of stress, says Dr. Jane Greer, a New York psychologist.

"Making a purchase can be very exciting. You're discovering something new, and you have the anticipation of finding something that's going to please you," she said.

Finance gurus even have a name for shopping in stressful times: the "lipstick indicator."
—Sarah Gilbert, “Pack up your troubles in your new gift bag,” The New York Post, March 24, 2003
2002 (earliest)
And even though Lauder thinks a recovery can't take hold without business leading the way, he too is not hopeful that it will be soon. That view, he explained, comes right from the mouths of women.

Or more appropriately, right on the mouths of women.

That's because his company developed what it calls a "leading lipstick indicator." A while ago, Estee Lauder noticed that whenever lipsticks sales went up, consumer confidence and spending went down. That happens, said Lauder, because women still want to feel good about themselves in tough times, but they can't always afford higher-priced items.

The compromise is lipstick.
—Christian Millman, “Retailers gather to look to future,” The Morning Call (Allentown, PA), January 15, 2002
Notes
For financial types, an indicator is an economic variable that shows the current state of some aspect of the economy. A leading indicator (or, more formally, a leading economic indicator) is an economic variable that shows the direction of future economic activity. The phrase lipstick indicator, which was coined by Leonard Lauder, chairman of Estee Lauder, posits that lipstick sales can be used as both an indicator and a leading indicator. Indeed, Lauder's original formulation for the phrase was leading lipstick indicator, as shown in the earliest citation. Why does it work? Probably because of the so-called lipstick effect: the tendency during tough times for consumers to purchase small, comforting items such as lipstick rather than large luxury items.