Right before the New Year’s holiday, the City of Philadelphia released some very important information as open data.
The city released a data set showing outstanding property tax balances for properties in Philadelphia, making the data available as both a static download and through an API.
I’ve always believed that this data was incredibly important – not just because it might be used to help the city improve its dismal record on collecting delinquent property taxes (which help fund both city operations and the School District of Philadelphia), but also because of the potential to encourage people to think differently about how data can be used to reshape city services.

Image courtesy of Flickr user ThunderKiss Photography.
So I examined this data (and another city data source) to determine how properties with an outstanding property tax balance are treated in the city’s permitting process. This is an important issue for analysis because permit applicants are likely to have resources on hand to conduct work on their property – this makes permit issuance a potentially important tool for ensuring repayment of outstanding tax bills.
I found that the city routinely issues permits to properties with an outstanding tax liability – over a two year period, and using a fairly conservative set of assumptions, this amounted to about $3.5 million essentially left on the table. The city might have been able to collect these outstanding funds, but failed to do so because it does not yet view permit issuance as a tool for ensuring tax compliance.
At a minimum, the analysis I conducted seems to have been fairly well received by city officials. Officials in the city’s Department of Licenses & Inspections have agreed to “audit the findings to determine whether there is a systematic issue that needs to be addressed.”
That’s mostly what I wanted – for a city department to think outside of its own organizational boundaries and find ways to use data from other city departments to do its job more effectively.
In some ways, that’s all I’ve ever wanted.
But if I could ask for a little more, it would be this – that we start to think differently about how we design government services in the digital age, and think about how we can use data to do it.
The City of Philadelphia – through the concerted effort of its open data team and technology department – has one of the richest collection of data APIs in the country. The opportunities this presents to elevate and inform policy discussions, and rethink how agencies do their work are staggering.
For example, the City of Philadelphia may enter into a repayment agreement with a property owner that is delinquent on their taxes – presumably after assessing the likelihood that the owner will abide by the agreement. The Philadelphia Gas Works (which is currently owned by the city) and other utility companies do the same.
What if the city and other local utility companies all shared data on delinquent accounts to better assess the likelihood that a property owner will repay their liability? If repayment is not likely then perhaps that property whould be moved along more quickly into the pipeline for acquisition by the city
What if the city decided to combine its own data with data from external sources – like listings on Airbnb – to inform new policies on short term rentals? Should properties with outstanding property taxes or safety violations be allowed for rent through third-party services? This is a legitimate policy question, and one that should be informed by open data.
What if the city decided to pool all of the disparate information from its agencies on city properties (and from other places) to build a model that would better predict the vacancy “tipping point” on a property – when an owner simply walks away and a structure becomes vacant.
Vacant properties can have significant detrimental effects on Philadelphia neighborhoods, so being able to predict when a property may become vacant can be crucial to focusing finite city resources on ensuring a positive outcome.
The city has an immense amount of data on properties, but often this data is not connected or falls under the purview of different agencies with separate missions and metrics for success.
Releasing open data is the first step in a longer process to reimagine the way that governments provide services and do their jobs. It’s incredibly gratifying to see the city taking these needed first steps around tax delinquency data.
Here’s hoping the next steps are not far behind.
Leave a Reply