What’s “Average” Class Size, 2008

Last May, HHSTA-Central looked at what “average” class size meant, and how to best determine just how many students are actually in the “average” class at Hinsdale Central as opposed to a nebulous staffing ratio most often quoted on this subject:

The HHSTA class size study at Central looked at all departments and the over 700 sections offered to Central Students that its members teach. The results showed:

Average All Class Size: 23.1
Average Core Class Size (English, Math, Science, and Social Studies): 22.4
Average Advanced Placement (AP) Class Size: 22.4
Percent of Classes with 13 or fewer students: 6.4%
Percent of Classes with 30 or more students: 9.6%

As was noted at the end of this post, this type of data fluctuates over time. So this year Illinois State Board of Education (ISBE) report card data was examined to see how class sizes in 2008 compared. All data below is via the ISBE website, which has a searchable database of Illinois school report cards going back to 2002.

First, the comparison within district:

District 86 Average Class Size – 2008:
Hinsdale South:  19.4
State Average: 19.6
Hinsdale Central:  21.7

Hinsdale Central average class size, as determined by ISBE in 2008, is larger than both the state average and the average at Hinsdale South. How does this compare with other schools locally? For this comparison, ISBE data was compared with other high schools in our conference:

West Suburban Conference Silver Division Average Class Size 2008:
Lyons Township:  18.8
Proviso West:   19.0
Oak Park & River Forest: 19.2
Downers Grove North: 19.6
York:    21.4
Hinsdale Central:  21.7
Glenbard West:  26.1

Hinsdale Central average class size, as determined by ISBE in 2008, was larger that of all but Glenbard West. The next question asked was how did this data compare to the highest performing schools in Illinois? For this question, the ISBE data for the top 10 public schools from the Chicago Sun Times 2008 “Top 50 High Schools in Illinois” (excluding CPS schools) was compared :

Top 10 Illinois High Schools Average Class Size 2008:
Glenbrook North:  18.2
Deerfield:   18.5
Lyons Township:  18.8
New Trier:   20.0
Maine South:   20.2
Lake Forest:   21.3
Adlai E Stevenson:  21.6
Hinsdale Central:  21.7
Naperville Central:  22.2
William Fremd:  22.7

Hinsdale Central average class size, as determined by ISBE in 2008, was larger than all but two of the top 10 public schools in Illinois.