It just got more difficult for charter school opponents to make their case. Research conducted by a Stanford University economist showed that New York City students who entered lotteries and won spots in charter schools outscored students who entered the same lotteries but did not win spots.

Research also showed that the charter school students, who in New York City tend to come from poor and disadvantaged families, scored almost as well as students in the affluent Scarsdale school district.

Many educators and school personnel have dismissed the successes of charter schools -- public schools that enjoy wide-ranging autonomy under the leadership of citizen boards charged with fulfilling goals set in their charters.

Charters' critics frequently say that the schools have an advantage in teaching only students whose parents were motivated enough to enroll them there.

But these new study results tell a different story -- one that should cause those critics to think again.

The study did not reach any conclusions about why charter schools succeeded, but noted that many had extended school days and school years, mandatory Saturday classes, performance-based pay for teachers and a disciplinary policy that punishes small infractions and rewards courtesy.

President Obama, as reported on our front page Monday, has spoken in favor of longer school days and years.

Education Secretary Arne Duncan recently said states risk losing a chance at millions of stimulus dollars if they are not open to charter schools.

Many school officials, including officials in Charleston County, have been cool to charters, which they say take money away from schools that need it more.

However, that attitude seems to be thawing, if not about charter schools per se then at least about school choice in general.

The New York City study should provide impetus for educators to open their minds to charter schools and to recognize them as an innovative concept worth trying.

That doesn't mean giving carte blanche to people who want to start charter schools. Each request should undergo rigorous scrutiny and schools' performances in reaching their charters' goals should be tracked.

If a charter school succeeds, an entire district can benefit. And if it doesn't, it should lose its charter.

The encouraging new data from New York provide additional reason to give charter schools a fair chance to flourish.