The percentage of students who score above the 50th percentile differs substantially depending on the test used and on how the test-makers determine the 50th percentile.
In its latest achievement report and in the highlights to its achievement report, School District 65 has reported the percentage of District 65 African American, Hispanic and white eighth-graders who scored above the 50th percentile, using an abbreviated version of the Stanford Achievement Test, edition 10 (SAT-10). The results on this test give a positive picture of achievement. For example, according to the test, 68% of African American, 67% of Hispanic, and 97% of white eighth-graders scored above the 50th percentile in reading in 2010.
The District, however, does not report statewide data which would give these percentages some context and does not report 50th percentile data using other measures or tests. The other data show District 65 is making good progress, but it is much less than that portrayed by the SAT-10.
The SAT-10 on a Statewide Basis –
High percentages of District 65 eighth-graders score above the 50th national percentile on the SAT-10. To put this in context, though, high percentages of all Illinois students score above the 50th national percentile on the SAT-10. The SAT-10 produces much higher results than other tests.
The Illinois State Board of Education (ISBE) reports that 72% of all Illinois eighth-graders scored above the 50th national percentile in reading on the SAT-10 in 2009, and 75% scored above the 50th percentile in math. According to these figures, Illinois students are performing much better than the national average – sort of like the kids in Lake Woebegone, the mythical place where all children are above average.
In the same year, though, Illinois students performed very close to the national average on the 2009 National Assessment of Education Progress (NAEP). NAEP is given every two years to a representative sample of students in fourth and eighth grades from every state. The test is sponsored by the U.S. Department of Education and is often referred to as the Nation’s Report Card.
On NAEP, 53% of Illinois students scored above the 50th percentile in reading, and 51% in math. These percentages are very close to the national average of 50%, and are about 20 points lower than the percentages generated by the SAT-10.
The method used to determine the 50th percentile is vastly different for the two tests. According to ISBE, an abbreviated version of the SAT-10 is given to Illinois students as part of the ISAT. A student’s score on the abbreviated version of the SAT-10 is extrapolated to a full-length score, and a percentile rank is then obtained from a table prepared in 2002 based on a national norm sample.
For NEAP, the median scale score of all students in the nation on a given test is determined, and the percent of Illinois students who scored above that median score represents the percent who scored above the 50th percentile.
Paul Zavitkovsky of the Urban Education Leadership Program at the University of Illinois-Chicago says, “The NAEP reflects a broad national sampling conducted every two years by the national Institute of Education Sciences. The SAT-10 is based on a sample population that’s renewed only once every ten years by a single commercial publisher. When there’s a conflict, I think there’s good reason to privilege the NAEP.”
Same Pattern at District 65
The statewide pattern in which the SAT-10 generates substantially higher results than other tests is carried down to the local level at District 65.
In response to a freedom of information act request, the District provided data to the RoundTable showing the percent of District 65 African American, Hispanic and white eighth-graders who scored above the median scale score of all Illinois eighth-graders in both reading and math on the 2010 ISATs (the 50th Illinois percentile).
The data shows that much lower percentages of African American and Hispanic students scored above the 50th Illinois percentile than are reported scoring above the 50th percentile on the SAT-10 – the difference for these ethnic groups is between 12 and 27 percentage points.
The District also provided data to the RoundTable that shows the percentage of District 65 African American, Hispanic and white students who scored above the 50th percentile on the Measures of Academic Progress Test (MAP). Again, the data shows that much lower percentages of African American and Hispanic students are scoring above the 50th percentile on MAP than on the SAT-10. The District evaluates teachers based in part on the number of students who exceed the 50th percentile on MAP at the beginning and end of the school year.
The accompanying table shows the percent of D65 eighth-graders, by ethnic group, scoring above the 50th percentile on the SAT-10 that was part of the 2010 ISATs, the percent scoring above the median score of all Illinois students on the 2010 ISATs (the 50th Illinois percentile), and the percent scoring above the 50th percentile on the spring 2010 MAP.
Another data point is the EXPLORE test which is given to District 65 eighth-graders by ETHS. In its October 2010 achievement report, ETHS listed the percent of designated numbers of African American, Hispanic and white students in its 2010-11 freshman class who scored above the 50th percentile on EXPLORE: for African Americans – 61% in reading and 64% in math; for Hispanic students – 60% in reading and 71% in math; for white students – 95% in reading and 97% in math.
The RoundTable does not have sufficient data to determine how closely the student groups for whom ETHS reports EXPLORE scores match up with the eighth-grade classes at District 65. The freshman class at ETHS is substantially higher than the prior year’s District 65 eighth grade class. In addition an
EXPLORE score is not reported in the ethnic groupings for about 12% of the African American students and about 30% of the Hispanic students in the ETHS freshman class of 2010-11.
In its editorial pages, the RoundTable has urged School District 65 to report the percent of students, by ethnicity, scoring above the median scale score on the ISATs (the 50th Illinois percentile) and to report the percent of students, by ethnicity, scoring above the 50th percentile on MAP. On Oct. 13, the School Board decided that the District would report the percent of students, by ethnicity, scoring above the 50th Illinois percentile. District 65 administrators, however ,decided not to include that information in the District’s highlights that were posted on the District’s website in mid-December.
% D65 8th Graders Who Scored Above the 50th SAT-10 Percentile, the 50th Illinois Percentile and the 50th MAP Percentile
SAT-10 Ill. %ile MAP
Af. Am. 68 41 49
Hispanic 67 50 58
White 97 89 92
Af. Am. 77 56 58
Hispanic 82 60 66
White 98 92 93