Question 7 is fair because it spreads the burden of building housing

ON THE FIRST day of my undergraduate housing policy class, I show my students a headline from the satirical website McSweeney’s that encapsulates the problem at the heart of the Commonwealth’s affordability crisis. “Housing should be affordable,” it reads, “except when I sell my house for a million dollars.”

Nobody wants denser housing built only near them, so no city or town wants to be the only one that builds. Spread McSweeney’s logic across all 351 cities and towns in Massachusetts, and you get a statewide housing shortage. The only way to break the zoning logjam is a statewide mandate, and Question 7 is a good first step. Anyone concerned about housing affordability should vote for it.

Economists broadly agree that housing in “superstar cities” and regions like Greater Boston is unaffordable primarily because we have not built enough. Demand for living in thriving, dynamic, and innovative places like Massachusetts far outstrips supply. The shortage shows up as a gap between the cost of a house and the cost of building it, implying that house prices and rents are high because regulations have made buildable land artificially scarce.

One such regulation is particularly notorious: minimum lot sizes. Localities have used large-lot requirements for over a century to limit density and keep the riffraff out. Among areas zoned for single-family homes, 66 percent nationwide have minimum lot requirements above 5,000 square feet and 7 percent require more than half an acre. These regulations are more common in affluent areas with fewer minorities. By limiting land supply, they drive up housing costs for everyone.

Question 7 would require that single-family homes be allowed on any lot of at least 5,000 square feet with 50 feet of street frontage and access to public water and sewer. This would let market forces gradually densify cities and towns as developers subdivide large lots, pushing down housing costs. Both nationwide analyses and local policy studies provide strong evidence that rolling back minimum lot sizes reduces house prices and rents over time. Houston, for instance, cut minimums in 1998, leading to a boom in townhomes that added thousands of homes to supply.

Opponents of Question 7, led by the Massachusetts Municipal Association, cry foul because it limits the autonomy of local governments, which they argue are best positioned to enact thoughtful zoning laws. They also claim that towns will voluntarily implement other, better policies.

This is exactly the thinking that has led to our affordability crisis: We have failed to build because the balance has tipped too far toward local control. Cities and towns limit construction to free-ride on housing and density built elsewhere, so nobody builds enough housing.

The resistance to the MBTA Communities Act shows that municipalities will not meaningfully relax zoning on their own, even with significant carrots and sticks. And when a law leaves wiggle room, towns exploit it: Marblehead complied with the law by rezoning a golf course that will never be redeveloped.

The best way to overcome this is a simple bright-line policy that spreads the burden of density statewide through an across-the-board limit on lot sizes. This approach has gained momentum in recent years, with several states adopting similar limits.

Question 7 is a modest step in this direction. It will not build a monstrous ziggurat next door. Instead, it will subtly change neighborhood character by allowing a few smaller single-family homes on land that would otherwise hold one large house.

Some may argue that the 5,000-square-foot limit is too small and too one-size-fits-all. But any bright line is imperfect, and one that spares more towns would build far less of the housing we need and would not spread the burden. Furthermore, the water and sewer requirement means that Question 7 will not affect rural areas. Finally, the towns where Question 7 would have the greatest impact are precisely those that have used minimum lot sizes to avoid doing their share. They should not get a pass for their past resistance.

Massachusetts needs more housing if we want to remain a place where smart, talented people want to move. Question 7 is a simple way to stop the zoning race to the bottom among cities and towns and force everyone to take on a bit more density for the Commonwealth’s greater good. Everyone worried about rising house prices and rents should support it.

Adam Guren is an associate professor of economics at Boston University, where he teaches courses on housing policy.