While monthly same-store sales, also known as comps, aren't the be-all and end-all for investors, they're a useful way to gauge consumers' responses to certain retailers' fashion offerings. Given this year's rather dicey view on retail investing, September's same-store sales data among teen-focused retailers gave investors plenty of food for thought.

Among the sector's bright spots, Abercrombie & Fitch (NYSE:ANF) has been enjoying a particularly strong year, despite facing some tough comparisons to last year's results. Its September comps increased 10%, compared to analysts' forecast of 5.5%, reflecting a particularly strong month. It even increased its full-year earnings forecast.

American Eagle Outfitters (NASDAQ:AEOS) also blew the doors off, with same-store sales increasing 19% -- and that's compared to a very strong 13% increase last September. Aeropostale (NYSE:ARO) also beat expectations, with an 8.5% increase for the month compared to the 5.6% increase analysts had forecast. However, Aeropostale had an easy comparison, since its same-store sales last September dropped 4.2%.

On the other hand, Gap (NYSE:GPS) has become a habitual underperformer on this metric and many more, and September was no different. Same-store sales at Gap dropped 3%, compared to a 6% decrease this time last year. Gap's share price has been rising lately, as some investors apparently bet that the company's strong balance sheet and brand will see it through what continues to be a long period of tough times. I still see few signs that this company will right its ship in the next couple of months, especially given continuing decreases in its comps. I still think Gap's a leap of faith right now, with few signs of strengthening sales.

After retail's long, tough summer, when worries over turbulent fashions and macroeconomic concerns kept investors away from the sector, the market has recently seemed to warm up to the industry and its shares. Of course, we're now edging closer to the holiday season. It's logical to suppose that companies currently showing strength should be able to maintain that momentum into the big winter shopping season.

For more on retail, see the following Foolish articles:

American Eagle Outfitters and Gap are Motley Fool Stock Advisor recommendations, while Gap has also been recommended by Motley Fool Inside Value .

Alyce Lomax does not own shares of any of the companies mentioned. The Fool has a disclosure policy.