This quarterly market report is provided by Dr. Kevin Gillen, an economist at the Real Estate Department of the Wharton School and Fellow of the University of Pennsylvania. He analyzes the Philadelphia real estate market using the city’s real estate database through Hallwatch , a watchdog group. The results are published in a research paper called Philadelphia House Price Indices each quarter as a public service to the Philadelphia real estate community. Here’s his methodology [pdf] .
Kevin does a great job parsing out the market and its a pleasure to share his results on Matrix —Jonathan Miller
Read the Hallwatch article on the market: Philly real estate: fewer sales, higher prices in some areas 
Here is one of the key points :
Although Philadelphia’s house prices may be resisting their continued declines, home sales continued their downward plunge this spring. Even though spring is normally the busiest time of year for housing transactions, only 4,546 dwellings changed hands under arms-length conditions this past quarter. This is a 25% drop from spring 2007, and a 42% drop from the housing boom’s peak in the summer of 2005.
More discussion concerning the report [Hallwatch.org] . Hallwatch  is a private and independently maintained watchdog website that does a lot of in-depth, independent and investigative pieces on city politics, as well as real estate.