One other good way to tell is to walk around that neighborhood. Look at the homes. When more homes look taken care of than not than that may be a sign it is moving on up. You also should look at the crime rate, school stats and homes sold and prices. The Baltimore Sun always has neighborhood sold prices in the Real estate section. Check it out and good luck!
Cher Varnum-Glenn
ZipRealty
410-913-1477

In this area the number one indicator is the number of "rehabbed" homes for sale and the price trend of those properties relative to the overall RE market. Improved crime stats follow homeowners (vs renters) as well. For example in Patterson Park, Fells Point, Canton, Charles Village, and Federal Hill areas of Baltimore city hundreds of top- to -bottom total rehabs sell every month, prices,like everywhere else are down from 2 years ago - but not by as much as the counties. Also there are lots of new listings coming on every month bc the builders continue to be confident about the direction the neighborhood is going, so while many sell, inventory may not appear to decline relative to sales.
A good look at what is driving the turnaround tells you a lot, as well. Here the already massive and always growing Johns Hopkins Health Systems, campuses, hospitals, and emerging Bio-tech centers have brought students, doctors, professiors,researchers, and other capable buyers, renters, investors to the area - especially w/i walkinh/shuttle distance.
So, use it all and talk to the permit office re pace of permit applications, to see how the investment/construction bunch feel about the future of the neighborhood.
Hope this helps, I can also pull info for your neighborhood of interest specifically. 410-258-8935

Possible signs of a changing community:

new home construction

new area business and industry

decreasing number of homes on the market for sale

decreasing crime rate

homes being revitalized