I get a little irritated when a study is needed to prove something that should be obvious to a six-year old, and then the results are reported like we've discovered something counterintuitive and ground breaking.
But then I take a breath and back away from the keyboard and remind myself that there really are people -- "experts" even -- who don't get it.
So, I'll toggle off the snark and join Joanne in calling attention to the research and hope that a few more people start to get it.
Our results indicate that the increased competitive pressure public schools faced following the introduction of Florida’s Tax Credit Scholarship Program led to general improvements in their performance. Both expanded access to private school options and greater variety of options that students have in terms of the religious (or secular) affiliations of private schools are positively associated with public-school students’ test scores following the introduction of the FTC program. The gains occur immediately, before any students leave the public schools with a scholarship, implying that competitive threats are responsible for at least some of the estimated effects. And the gains appear to be much more pronounced in the schools most at risk to lose students (elementary and middle schools, where the cost of private school attendance with a scholarship is much lower) and in the schools that are on the margin of Title I funding.