Housing and Urban Development Secretary Ben Carson. (Kevin Lamarque/Reuters)

THERE IS a painful, chronic lack of affordable housing in urban areas. The causes are often rooted in local law and policy, notably exclusionary zoning that limits high-density projects so as to protect the property values of single-family homeowners. So the first point to make about the changes in federal housing aid that Housing and Urban Development Secretary Ben Carson rolled out on April 25 — including potential rent hikes and work requirements — is that, at best, they would amount to a Band-Aid on a Band-Aid. The second is that there is little chance Congress will adopt his plan: It is a rehash of ideas lawmakers rejected earlier this year in the course of increasing federal housing spending for fiscal 2019, contrary to what Mr. Carson had recommended. The announcement seems designed as Mr. Carson’s response to President Trump’s April 10 executive order demanding that all agencies submit plans for linking safety-net benefits to work.

Still, given that the Trump administration seems so wedded to these ideas, it’s worth the effort to understand exactly what’s right and, mostly, what’s wrong with them. We’re all for reducing any disincentives to work. Mr. Carson’s plan addresses one by proposing that public-housing authorities calculate tenants’ rent every three years rather than annually, so as not to “tax” any short-term income boosts they may earn. It might also be smart, and a lot simpler, to base rents on gross income rather than income after adjustments and deductions. However, the Carson proposals offset those wise reforms by jacking up a tenant’s share of the rent from 30 percent of adjusted income under current law to 35 percent of gross income — a stiff increase for a group of people who are among the poorest of the poor. HUD is already testing pilot programs that charge some tenants 28 percent of their previous year’s average gross monthly income; the agency should wait for the results of that experiment.

As for work requirements, Mr. Carson’s proposal to permit public-housing agencies across the country to impose them suffers from the same flaw similar Republican notions for food and medical assistance have: It is a solution in search of a problem. As a January Urban Institute report on current HUD work-requirement pilot programs shows, only a very small percentage, usually less than 10 percent, of current housing aid recipients are nonworking, able-bodied, nonelderly adults. Many of those may already be subject to existing work requirements for other federal means-tested aid. As the Urban Institute notes, there is only one rigorous study of the long-term effect of such a program, from Charlotte, N.C.; it showed minimal improvement in work and income, the two key metrics of the “self-sufficiency” Mr. Carson wants to achieve.

The irony is that, under a law President Barack Obama signed in 2015, HUD was preparing to increase from 39 to 100 the number of housing authorities free to experiment with work requirements and other locally tailored policies to improve tenants’ earning potential and independence. Mr. Carson should carry out that program, closely monitor its results — then fashion policy based on the facts.