Housing has a data problem

According to latest UN estimates, 2.8 billion people worldwide lack access to adequate housing, while 318 million are homeless. Despite investing billions of dollars in solutions, governments and philanthropies have been unable to make a dent in the crisis.

- Rosanne Haggerty & Ruby Bolaria Shifrin

An underappreciated reason for this is the lack of basic infrastructure to track and understand baseline questions concerning housing. Major data gaps mean we often don't know which parcels of public land sit idle, how many units are vacant, and where development proposals stall.

And without common definitions for fundamental terms, it becomes difficult to make comparisons across contexts — "affordable housing" means one thing in London, another in Lagos, and something else entirely in Los Angeles. Worse, the data that do exist are rarely accessible to policymakers and researchers.

In most cities, no single authority is responsible for tracking which public entity owns which parcel of land. Transit agencies, school districts, and planning departments each hold fragments of information that never connect. Zoning codes vary widely, not just between countries but also between neighboring municipalities.

This fragmentation produces bad policy. Without a full picture of the available resources and the factors that affect housing supply, policymakers cannot reliably identify effective interventions. As a result, a city might invest heavily in subsidized construction while sitting on publicly owned land that could be developed more cheaply. Governments set ambitious housing targets but are unable to track progress or remove bottlenecks, which effectively shields them from any real accountability.