Another week, another update to our Philadelphia Housing Index. Last week, we provided indices for school catchment areas. This week: neighborhoods.
We calculated indices for each of Philadelphia’s 67 neighborhoods.  Similar to the Elementary School Indices, these neighborhoods are fairly small, and require more smoothing over time than larger districts. Let’s look at some neighborhoods that we haven’t yet looked at on these pages.
The neighborhoods in the northeast remained remarkably stable over the last fifteen years. As an example, consider Bustleton. The neighborhood saw a 91% increase in prices between January 2001 and January 2007. That growth places it right in the middle of all neighborhoods over the time period. Prices then did relatively well during the Great Recession, falling by only 19% over the next six years. Those prices have stayed there, and the northeast has largely missed out on the rebound that comparably priced neighborhoods closer to center city—Fishtown, University City, South Philly—have experienced.
Manayunk was one of the most successful neighborhoods in the pre-Great Recession years. Prices grew 166% between January 2001 and January 2007. While Manayunk remains one of the more expensive neighborhoods in the city, it has still not fully recovered from the Great Recession, and prices have seen very modest growth over the last two years.
Overbrook and Haddington
Overbrook and Haddington in West Philadelphia have had similar trajectories over the last 15 years: both saw modest gains in the housing boom, lost those gains in the recession, and have seen very modest growth since. Overbrook, however, started from a significantly higher valuation, and has remained between 75% and 105% more costly than Haddington over the entire time period.
As an extra feature, we have also added to the portal a heat map of city indices. The calculations are more involved than the indices with fixed boundaries: we subtract from each sale the effect of its housing traits and its neighborhood’s seasonality, and then perform some simple spatio-temporal smoothing, which we hand-tune to the data.
The heat maps show a telling story of the Philadelphia housing market. The housing boom lifted all boats, as both already-hot spots and cheaper regions became much more valuable. The recession, however, affected the cheaper regions disproportionately: the already-cheaper spots in North and West Philadelphia became much cooler, while the hot spots in Center City remained relatively stable. Finally, the growth since has primarily occurred by the hot spots spreading outward from the center of the city: high priced regions have expanded out into University City, down into South Philly, and up into Kensington. However, the rising tide has decidedly not lifted all boats. The North Philly and West Philly neighborhoods hardest hit by the recession have also seen almost no increase in prices since. Moving boundaries, anyone?
See any interesting results? Have more ideas for new analyses? Let us know!
 We use neighborhood definitions from the Neighborhood Information System by the Cartographic Modeling Lab at the University of Pennsylvania. http://www.cml.upenn.edu/nis
Jonathan Tannen, Ph.D., was previously a Director at Econsult Solutions, Inc (ESI). Jonathan’s dissertation research used GIS and large-scale computational techniques to develop a Bayesian method to measure the movement of neighborhood boundaries.