Inclusionary Zoning Affordability Audit

Summary

Chicago's analysis of its inclusionary zoning ordinance found that the affordable unit requirement, combined with density bonuses that allowed developers to build more total units, produced meaningful affordable supply without depressing overall residential construction. The evaluation used a synthetic control comparison against cities with similar market conditions that did not adopt inclusionary requirements. The finding runs counter to theoretical predictions from real estate economics, which suggested requirements would depress supply. The density bonus appears to have offset the cost burden effectively.

Research question

"Does requiring affordable units in market-rate developments increase affordable supply without reducing overall production?"

Methodology

Result

Positive

Affordable units produced: +1,200 units above baseline; total production unchanged relative to synthetic control

Evidence strength

Limited

Observational or pre-post design; correlation not necessarily causal.

Replication status

Partially replicated