ONE OF THE long-standing misperceptions about charter schools is that they cherry-pick the better students from an area, resulting in higher test scores than in comparable regular public schools.
A new study by Stanford University economist Caroline Hoxby indicates that so-called "creaming" is largely a myth misused by critics of school choice.
The study examined New York City charter schools, which generally draw students from disadvantaged families, and compared them to standard public schools in the both the city and in affluent suburbs.
Students who attended inner-city charter schools from kindergarten through eighth grade improved their academic achievement considerably. In fact, the test score gap between low-income minorities and affluent whites was reduced by 86 percent in math and 66 percent in English.
The study found that the longer students remain in charter schools, the lower the achievement difference.
These results would be satisfying but not remarkable if the charter schools were selective. But they are not.
New York admits students to charter schools through a lottery system because there are far more applicants than available spaces.
One could argue that even with a lottery, charter schools would still be inadvertently cherry-picking because parents who enter the lottery are more interested, and thus, more involved in their children's education.
The study eliminated this bias by comparing students who won the lottery with those who did not. Those who were lucky enough to gain entry to charter schools did significantly better than those who went to standard public schools in the same area.
By third grade, the average charter student scored 5.8 points higher in math on standard achievement tests than those who lost the lottery and 5.3 points higher in English. Most tests are scored on a scale of roughly 475 to 800.
From grade four through eight, charter school students moved ahead by five more points each year in math and 3.6 points each year in English.
Hoxby found Chicago's charter school students' scores rising more than those in New York. Other researchers using the same methodology obtained similar results in Boston.
Moreover, the charter schools achieved better results at lower cost to taxpayers. Nationwide, on average, per-pupil spending is 61 percent of that of surrounding public schools, according to The Wall Street Journal.
Charter schools have the capacity to do a better job because they have greater academic flexibility, less bureaucracy and can remove disruptive students.
That does not mean all charter schools perform better than public schools. There are some that do not. But the structure of charter schools makes room for an improved learning environment as long as qualified, experienced teachers are employed and basic academic standards are followed.