Joe Biden is expected to name Connecticut Education Commissioner Miguel Cardona as his education secretary Wednesday. Given rumors about the president-elect tapping union officials for the job, this is a relief. Still, reformers and school-choice advocates shouldn’t let their guards down.

In a recent interview with the Education Writers Association, Stef Feldman, Biden’s national policy director, threatened to cut funding for “public charter schools that don’t provide results.” This, even as she vowed to fight for “the funds that our underperforming schools need, so our educators can succeed at their jobs.”

Got that? Team Biden’s position is that bad charter schools need to be defunded and possibly shuttered, while traditional failure factories just need more cash.

One assumption baked into this contradictory pair of claims is that charter schools get more money than traditional public schools. But as our recent study shows, in cities where charters are most common, charter students receive about two-thirds of the funding that their peers in traditional district schools receive.

Indeed, students in charters received less funding in 2018 than their counterparts in traditional schools in all 18 cities we examined. Charters received $7,796 less per student than traditional schools, a 33 percent disparity in favor of district schools.

In Gotham, charters received $6,178 less per student than traditional schools, or 19 percent. Students attending traditional schools received an average of $32,420 in annual funding while students attending charter schools received $26,242. In Atlanta, Little Rock, Washington and Chicago, the disparity widened to more than $10,000 per student.

This, even though the charters in our 18 cities serve more low-income students than district schools. Charters’ share of English Language Learners and students with disabilities is slightly smaller than those of traditional schools. Adjusting for this factor eliminated the funding disparities in Memphis and Boston. But the gap remained unexplained in the 16 other cities in our study.

If different levels of student disadvantage don’t explain the funding gap, what does? Our data point to two main culprits: local public funding and nonpublic funding.

Traditional schools in our cities received an average of $7,491 more in per-pupil revenue from local governments than did their charter counterparts. Eleven of our cities provided no or only trivial amounts of funding to their charters. In nine cities, states provided extra revenue to charters to compensate for the dearth of local revenue allocated to them. But in no city was the state boost enough to make up the difference.

Nonpublic funding widened the gap. Public schools receive revenue from various nonpublic sources, including philanthropy, school fundraisers, student fees and investment income. Contrary to popular perceptions, traditional schools often receive more revenue from these nonpublic sources than do charters. In 2018, nonpublic funding increased the charter school funding gap by $1,412 per student.

This disturbing gap in student funding — depending merely on whether a student enrolls in a public school with “charter” in its name or not — isn’t new. Charter students have been getting shortchanged relative to their traditional-school peers since we first studied this question in 2003. The problem is getting worse, even as charters remain popular and serve ever-more students, especially in cities.

In the 14 cities we have studied since 2013, the charter funding gap has increased by 26 percent in real terms since then. In the eight cities we have examined since 2003, the gap has more than doubled over that time period.

In short, Team Biden’s commitment to defund underperforming charters while pouring more cash into failing traditional schools defies data and logic. The implication is that charters have more resources to begin with. But that simply isn’t true. If faced with two struggling schools, one charter and the other traditional, it’s the charter that likely suffers from a lack of resources.

A student shouldn’t be valued less simply because her residentially assigned public school was a poor fit. Policymakers need to reform school-funding laws so that students receive their fair share of resources even when they choose a charter. It is a simple matter of justice.