Methodology

We use a few key statistics to rate the schools in two different ways. One way is to rank schools based on different criteria; on the charts, a school’s ranking appears in the far right column. For the counties, schools are ranked on three different attributes, and they are ranked only in relation to other schools within that county. The three attributes used to rank schools in the counties all point to school quality. They are: the percentage of students who meet or exceed state goals on the Illinois Standards Achievement Test (which we refer to as “test scores”); the pupil-teacher ratio, an indication of how many educational professionals—not only classroom teachers—are available to each child; and instructional spending per pupil.

Our guiding principle for these county ratings is that a good school has small classes and high test scores and spends generously on educating its pupils. Thus, higher test scores and greater school spending, combined with lower class sizes or pupil-teacher ratios, contribute to a higher ranking.

The attributes are weighted to determine a school’s final ranking; test scores count the most, pupil-teacher ratio next, and spending least. Points are assigned by quartile: Out of all a county’s schools, the one-fourth that have the highest test scores receive the most points for that category, and the one-fourth with lowest scores receive the least.

The schools are ranked by their final point totals; in the event of a tie, they are listed alphabetically. We do not publish the point totals, because they vary from county to county depending on the number of schools and the range of test scores. And to reiterate, a school’s ranking is relative only to the other schools in the same county.

Our ranking for schools in the city of Chicago is a little different. Because these schools all belong to the same district, the numbers reported for the average pupil-teacher ratio and for instructional spending per student are the same for all 400-plus Chicago schools. For that reason, we have ranked the city schools based purely on their meets/exceeds scores. In a separate chart, however, we have singled out ten Chicago schools as “promising places.” To identify these schools, we applied the same ranking system we used with the county schools, but Chicago schools were rated on only two counts: meets/exceeds scores and average class size. For average class size, we used the figures reported for third grade. For schools without a third grade, we used the sixth-grade figure.

Our second rating is an efficiency grade, and this we have applied equally to all Chicago and county schools. On the charts, it is the third column from the right. We evaluated the relationship between a school’s test scores and its per-pupil instructional spending: With the kind of money a school is spending, how are its students faring on state tests?

Here again, schools were divided into quartiles within their counties (or the city), with the schools whose spending is lowest relative to their test scores receiving As, and those whose spending is highest relative to their test scores getting Ds. Schools with As are more efficient: They spend less but get high academic performance.

A Guide to the Columns in the Charts

GRADES IN SCHOOL: This column indicates the different grade levels within a school.

TOTAL SCHOOL ENROLLMENT: The figures listed reflect the number of students enrolled in the school as of September 30, 2008.

PERCENT LOW INCOME: This figure, derived from a federal definition of “low income” for households, is used not as an indicator of school quality but to help describe the student body.

AVERAGE TEACHING EXPERIENCE: This statistic cuts both ways. Experienced teachers are seasoned in the methods of reaching students, but they also command higher salaries than newer teachers do. Teacher experience is given as an average over an entire school district. (That’s why the same figure is listed for each school on the Chicago chart.) When we last published these charts in 2006, CPS reported its average years of teacher experience as 13.4; this year, the average is 12.7. Retirements and other staff changes over the past four years have resulted in Chicago teachers being, on average, 5 percent less experienced than they were in 2006.

The district that has the least experienced teachers, on average, is Consolidated School District 158, which serves fast-growing Huntley, Lake in the Hills, and Algonquin. In the mid-1990s, the district had only one elementary school and one high school; it now has five elementary schools, two middle schools, and a single three-campus high school, for a total of 8,200 students. Clearly, staffing those new schools has kept the district’s average years of teacher experience low—but note on the McHenry County chart that three District 158 schools landed in the top ten. Those inexperienced teachers are apparently performing well.

Grass Lake School in Antioch reports the most experienced teacher population in the Chicago area, with an average 18.5 years in service. (This school appears in the online charts, not the printed ones.) It’s a single-school district with fewer than 20 full-time teachers; the intimacy of the setting may contribute to the longevity figure, but because the number of teachers is so small, the average is easily influenced by the tenure of a few long-timers.

AVERAGE TEACHER SALARY: Teachers ought to be paid well, and at most of the region’s top-ranked schools, they are. As was the case in our 2006 report, elementary school teachers are paid best in a broad swath of DuPage County from Clarendon Hills to Naperville. Four years ago, that encompassed four districts (181, 203, 62, and 201); it now also includes District 53 in Oak Brook. All five districts report average salaries of at least $77,000, up 13 percent from the minimum reported by the four districts in 2006.

The lowest average salary is $38,040, at Grays- lake Prairie Crossing Charter School, a school singled out in Chicago’s April 2009 look at local charter schools (Charting a New Course).

The median salary for teachers in all Chicago-area primary schools is around $59,000—or about 12 percent below the average salary at Chicago Public Schools. On our charts, several districts in outlying counties (Kane, Will, and McHenry) pay below that $59,000 level, but their cost of living is lower than in many locations closer to Chicago.

AVERAGE CLASS SIZE AND PUPIL-TEACHER RATIO: The charts show the class size for a school’s kindergarten and first, third, and sixth grades (although outside Chicago, most schools have only some of these grade levels), as well as the pupil-teacher ratio for the entire school. Classes generally get bigger as kids get to higher grades. We report each school’s overall pupil-teacher ratio because of the lack of uniformity in how schools designate grade levels, as noted under “Grades in School,” but also because many students don’t spend all their time in one classroom or with one teacher. They may change rooms for certain subjects, and sometimes specialty teachers (such as for reading assistance) move among classrooms. The pupil-teacher ratio gives a more accurate count of how many certified teachers come in contact with an individual student than does average class size alone.

There is debate among education experts about how much influence class size has on a school’s success or failure. Chicago’s premise is that smaller classes lead to a more effective school experience for students and teachers alike.

SPENDING PER STUDENT (INSTRUCTIONAL): This is a measure of how much of the school district’s money goes to teaching rather than to construction, transportation, debt service, or other operations. The idea is not that money spent equates directly to student achievement; instead, this figure shows a community’s commitment, via taxation, to high educational standards. There is no denying that in top-spending districts—such as Rondout District 97, west of Lake Forest ($13,083 per pupil), or Sunset Ridge District 29 in Northfield ($11,915), the two districts that spend the most of any in the region—those abundant resources can facilitate student performance. Nevertheless, Rondout did not make it to the top 15 Lake County schools (it ranked 38th). What’s more, it got an efficiency grade of D. Two District 29 schools made it into Cook County’s top 30.

PERCENTAGE MEETS/EXCEEDS: In Illinois, each public school student from third through eighth grade annually takes the Illinois Standards Achievement Test (ISAT), which evaluates student performance in reading and mathematics. (Fourth graders and seventh graders are also tested in science.) On our charts, the number in this column, derived from a school’s overall performance on all ISAT testing in the 2008–09 school year, represents the percentage of the school’s students who met or exceeded state standards.

The suburban elementary school with the highest meets/exceeds figure is Madison, in Hinsdale (99.6). Oak (Hinsdale), Highlands (Naperville), and Willowbrook (Glenview) each have 98.3. Four years ago, the top schools were all in the 97 percent range.

At the top of the city schools are four that specialize in teaching gifted students—Decatur Classical, Keller Gifted, Lenart Gifted, and Poe Classical—where 100 percent of students meet or exceed state goals. With 97.2 percent of its students meeting or exceeding state standards, Edgebrook, a school on the Far Northwest Side, is the city’s top-scoring school that is not a gifted specialty school; it took the same spot in our 2006 report.