Photo by Katie Little for CNBC.com A BCBG model

Since you people loved my hemline theory story so much, I thought I’d add a bit more of my thinking on the subject.

What really matters for predicting the economy is not whether hemlines are rising or falling. It’s whether the fashion industry can successfully launch new trends into the market.

If a trend pushed by designers sells well, it is an indicator that consumers are willing to invest more in clothing. So the thing to watch here is not the absolute length of skirts but whether people are following whatever the new length is.

So if next spring you see lots of women walking around in things that look like what you can see on the runaways this week, it’s a sign of a strong economy.