Crashing Down! (and up and down again).
In chapter 4 of The Long (and Short) of It, I write about the Skirt Length Theory, an outdated way to measure the economy based on the length of women's skirts. So I was surprised to see this clip on YouTube from a 2006 video called History's Hidden Engine about that very topic, even though today’s economists and historians pretty much agree that 21st-century styles, which see hemlines at every length, make the Skirt Length Theory entirely obsolete. I haven't seen the whole film, but there's some great footage in this clip: dancing flappers, early catwalks and decades-old fashion shoots.
Here's my take, from Chapter 4 of "The Long (and Short of It): the Madcap History of the Skirt":
Since the Depression and the subsequent finicky nature of hemlines through World War II, the height of hemlines has been used as a barometer to determine the outlook of the stock market. Though market analysts didn't pick up on the connection at the time, the Skirt Length Theory, an indicator of market value and consumer behavior, was born. The thinking behind the theory goes that shorter skirts tend to appear in times when general consumer confidence is high, and when hemlines fall and skirts are worn longer, the overall outlook is gloomy and fearful. (The same goes for lipstick sales, according to Leonard Lauder, the chairman of Estée Lauder.) In 1971, hot pants were the rage, and the advice at the Dow Jones was, "Don't sell until you see the heights of their thighs!" Now, in the 21st century, with hemlines all over the place, the Skirt Length Theory serves only as a cute colloquialism of the past.