What is IAR + ISA + HS Assessment?
Illinois public-school students in grades 3 through 8 take the Illinois Assessment of Readiness (IAR) in English Language Arts and Math each spring. The Illinois Science Assessment (ISA) is administered at grades 5, 8, and 11. High school students take the SAT (or PreACT in current administrations) as the state accountability assessment.
What does "% Proficient (Levels 4-5)" mean?
It is the percentage of students at the school who scored at Level 4 ("Met Expectations") or Level 5 ("Exceeded Expectations") on the IAR 5-level scale. Levels 4 and 5 signal the student is performing at grade level or above. A higher number is better.
What does 53.9% mean for English Language Arts at Stevenson Middle School?
It means about 53.9 percent of students tested at Stevenson Middle School performed at grade level or above on the IAR + ISA + HS Assessment English Language Arts test in 2024-25. The statewide average for Illinois that year was 51.0%. The other students fell into the lower performance levels.
How is the state average calculated?
It is a weighted average, not a simple average of each school's number. We multiply each public school's score by how many of its students tested, add those together for all schools in Illinois, and divide by the total students tested that year. This way a big school with 1,500 students counts more than a small school with 50 students, which is the right way to ask "how did the typical student do this year?". District and county averages on this page use the same method, just scoped to that district or county.
Where does this data come from?
Illinois State Board of Education (ISBE), Report Card Public Data Set. Illinois Assessment of Readiness (IAR) for grades 3-8 ELA + Math, Illinois Science Assessment (ISA) at grades 5, 8, 11, plus the SAT / PreACT high-school assessment. Headline metric is the cumulative "Proficient" rate (Levels 4 + 5 on the IAR 5-level scale).
How often is it updated?
IAR + ISA + HS Assessment is administered once a year (spring). Results are released by the state in the summer or early fall. We refresh this page after each annual release.
