🚨We analyzed 138 million geocoded property tax records to quantify how municipal boundaries spatially overlap onto economic segregation in every US metro area—creating disparities in localities’ ability to fund public goods. And we made an interactive map of our results! [1/16]

We conceptualize ‘tax base fragmentation’: the spatial concentration (within a metro area) of property wealth in particular wealthy municipalities. The concept is intuitive—but not captured by existing measures of segregation & jurisdictional fragmentation academic.oup.com/ser/advance…

For the whole US, we produce two metrics: one capturing the degree of tax base fragmentation within every metro area, and another capturing the own-source fiscal capacity of every general-purpose local jurisdiction (measured as per capita property wealth; standardized by metro).

We find significant variation in tax base inequality across metropolitan areas—substantially driven by local government law, as state/regional variation in jurisdictional fragmentation interacts with (by spatially overlapping onto) different levels of economic segregation:

🔎We used the results to make an interactive web map that allows people to look up how the property wealth in their own metro area (or any other) is fragmented across different local municipalities. Our tool visualizes tax base fragmentation across the US: taxbasefragmentation.net/

What is unique about our measure is that we aggregate wealth at the level of the municipality: the funding base for many critical public services. This allows us to capture the difference btw (1) a *wealthy neighborhood* in a larger municipality, and (2) a *wealthy municipality*

That is why our visualization is different from familiar maps showing neighborhood wealth, though they might initially look similar (particularly in highly-fragmented metro areas). This jurisdictional variation has never before been quantified at scale, or visualized in this way.