Score disparity based on apples-to-apples comparison

To compare passing rates on eighth-grade and 11th-grade high-stakes tests, the Daily Herald combined the statistics of nine suburban high school districts and their respective feeder districts.

The composite districts are comparable to unit systems, where K-12 schools all are grouped under one administration.

The analysis also included the 20 unit districts in the Daily Herald coverage area, from Gurnee down to Bolingbrook, from Des Plaines west to Huntley.

The goal was to create an apples-to-apples comparison between how students fared as eighth-graders and how those same students fared when they reached high school.

On average, 76 percent of eighth-graders in these suburban districts met state reading standards in 2004.

Illinois next tested those students in 2007, when they were high school juniors.

That year just 61 percent of juniors at the average suburban high school met state reading standards -- a 15 percentage point drop from 2004 middle school levels.

The gap between last year's eighth-graders and last year's 11th-graders was even wider, since the state gave students extra time on elementary school math and reading tests and lowered the cutoff score to pass the eighth-grade math test.

In 2007, 87 percent of eighth-graders at the average middle school met standards in reading -- 26 percentage points more than at the average high school.

The discrepancy between 2004 eighth-graders and 2007 juniors was less pronounced in math.

In 2004, 67 percent of eighth-graders at the average suburban middle school met state math standards.

Three years later, 63 percent of juniors at the average suburban high school met state math standards.

But the parity was only temporary.

Last year, after the state lowered the cutoff score to pass the eighth-grade reading test, 90 percent of eighth-graders at the average suburban middle school met state math standards.