To the Editor:
The article “New Data Fuel Current Charter School Debate” (Sept. 8, 2004) describes a study by Caroline M. Hoxby suggesting that 4th graders in charter schools across the country perform better on state tests than their counterparts in regular public schools.
The next issue of Education Week (Sept. 15, 2004; print edition) carried a paid advertisement to which Ms. Hoxby was one of 29 signatories. It attacked a report on charter schools by the American Federation of Teachers that found that charter school students often do worse than comparable students in regular public schools (“AFT Charter School Study Sparks Heated National Debate,” Sept. 1, 2004). The ad charged that the AFT study “fails to meet professional standards,” primarily because it uses achievement data for only one point in time and makes use of only limited information on the family background of the students.
In fact, Ms. Hoxby’s study can be faulted on the very same grounds that she and her colleagues quite appropriately critique the AFT report. Like the aft comparisons, hers are based on student performance at only one point in time. But in contrast to the AFT report, which is based on data for individual students, she uses school averages. That means she uses no family-background data on students. Instead, she must take it as a matter of faith that students in charter schools have similar background characteristics as those in the “nearest” public school. Yet she accuses the AFT study of being “unsophisticated.”
It appears that Ms. Hoxby’s concept of “professional standards” rose dramatically between Sept. 8, 2004, and Sept. 15, 2004. Or perhaps her standards vary depending on the conclusions of the study in question.
Edward B. Fiske