The Pennsylvania state House has just passed an expansion of its existing k‑12 scholarship-donation tax credit program. The vote was a deafening 190 to 7 in a state that has voted Democratic in every one of the last five presidential elections.

Nevertheless, there is serious opposition to this expansion of education tax credits in the Senate, where several prominent lawmakers prefer a voucher bill. It’s not clear which path the legislature will ultimately take, but there seems to be considerable agreement on the goal: giving parents true freedom of choice in education.

A key point to consider, then, is which type of program is most likely to preserve the freedom and diversity of the education marketplace, thereby giving families a meaningful range of alternatives to choose from. I ran a regression study on precisely this question last fall (now forthcoming in the peer-reviewed Journal of School Choice). What I found is that vouchers impose a large and statistically highly significant burden of additional regulation on private schools while tax credits do not.

This is not the only advantage of the tax credit program, but it is a compelling one.