Use the dropdowns to view the results. You may view elementary or high school results by income range from 2004 through 2014.
Or, click here to find results by district and view school results dating back to 2004, the earliest year available.
First, select either elementary or high schools.
Select a year...
...and press submit.
Our Daily Herald Poverty-Achievement Index compares schools with similar percentages of low-income students instead of comparing, for instance, a school with mostly poor students to a school with mostly non-poor students. Click here to learn more about the index.
With our interactive database, you can ...
In the search box below, type in a school district's three-digit numbers (002 for District 2, 046 for District 46):
Select the district from the dropdown list then click
Or, click here to find results by year and income range.
With those averages, we were able to rank each school based on how much higher or lower it was from its income range's average - the Daily Herald Poverty-Achievement Index.
A school with a rank of 0 is exactly average for its range. Schools above average have a positive Poverty-Achievement Index score, schools below average would have a negative score.
The interactive graphic below demonstrates how deeply stratified Illinois schools are by income. It shows the average composite ISAT meets/exceeds score for each income range, with 0-9.9% being elementary schools with less than 10% of their student population qualifying as low-income.
Mouse over the chart to see results for each income level by year.
Note: The shaded areas in the chart indicate differences in the ISAT tests. Tests were changed starting in 2006 to comply with No Child Left Behind, and minimum standards for elementary schools were adjusted by the state starting in 2013. Click here for more information about ISAT scores.
In examining elementary schools, we found a strong correlation between a school's percentage of low-income students and composite ISAT scores.
The charts below illustrate the correlation between poverty and test scores. Each blue dot represents a school in Illinois. The black line is a trend line.
The graphs show that the greater the percentage of low-income students in a school, the lower the school's test scores. Click here to view an interactive graphic of 2014 elementary schools and here for the 2004 version.
High school PSAE scores show stratification in the same way as elementary schools.
Because of a smaller sample size, we divided high schools into eight groups instead of 10, with 0-12.4% being schools with less than 12.5% of their student population qualifying as low-income. Minimum standards were not adjusted for high schools as they were with for elementary schools.
While high schools seem to have made progress since 2004, schools at the wealthiest income levels generally had more students making minimum standards than schools at the poorest income level.
Here's the percentage-point gap between average composite meets/exceeds PSAE score for the wealthiest income range (0-12.4% low income) and the poorest income range (87.5-100% low income).
The gap between the wealthiest and poorest income ranges grew larger in 2014 compared to 2004.
The correlation between scores and income levels for high schools is also strong.
Click here to find all the data and files for this web app.
Our Poverty-Achievement Index is based on a statistical technique called a Z score that shows how far something is from an average.
Click here to learn more about z scores.
Z scores are based on the idea of the normal curve: Generally if you have enough data, most of it will fall around an average. The rest will distribute on either side of that average.
We can measure how spread out the data is using standard deviations. A Z score is simply the number of standard deviations something is from the average.
So, an item that is one standard deviation higher than the average has a Z score (or Index score) of 1. An item that is one standard deviation lower than the average has an Index score of -1. And an item that is exactly average has an Index score of 0.
To make a more apples-to-apples comparison of Illinois schools, we sorted schools into ranges based on the percentage of low-income students they serve. Then we calculated the average composite ISAT and PSAE scores for each range.
With those averages, we were able to sort each school based on how many points higher or lower it was from its income range’s average - the Z score.
Our primary goal was to use them to see how a school performed compared to those with similar levels of low-income students.
Below is a chart showing Tefft Middle School's Z scores since 2006 compared to all schools with similar percentages of low-income students.
We see that Tefft has been above average for several years.
While we've sought to provide a more apples-to-apples look at Illinois schools with our Poverty-Achievement Index, correlation itself is not causation. Correlation is like a red flag that travels with a group - it may signal something significant but groups carry a lot of flags. The group itself needs to be examined to determine that significance.
In addition, income level is only one measurement. Other factors, such as the percentage of students who aren’t fluent in English, can affect test results as well.
Of course, the perfect normal curve isn't often found in nature. Very small sample sizes can skew the average.
For instance, take a set of four people. Three of them have $50 and one has $100,000. The average for those four people is $25,037.5, which is mathematically accurate but not a very accurate description of the four people.
But if you had 1,000 people, with 999 of them having $50 and only one with $100,000, the average for that group would be $149.95 - far closer to being an accurate description.
Here are the averages and medians for eleentary and high schools for each 2014 low income range.
|Elem. income ranges||Avg. ISAT||Median ISAT||H.S. income ranges||Avg. PSAE||Median PSAE|
|0- 9.9%||84.0||84.9||0 – 12.4%||74.2||74.6|
|10-19.9%||78.0||78.6||12.5 – 24.9%||67.2||68.8|
|20-29.9%||72.3||71.8||25 – 37.4%||58.2||57.9|
|30-39.9%||65.5||65.1||37.5 – 49.9%||51.3||50.3|
|40-49.9%||60.5||60.5||50 – 62.4%||44.9||44.8|
|50-59.9%||56.2||56.2||62.5 – 75%||36.7||35.4|
|60-69.9%||52.0||51.2||75 – 87.4%||34.7||32.4|
|70-79.9%||47.2||46.5||87.5 – 100%||21.8||18.0|
The ISAT test changed in 2006.
Although results by income were consistent with other years, 2005 was a transitional testing year that does not adequately represent results from pre-NCLB testing.
Many high-ranking schools have selective enrollment. Others, such as some magnet or charter schools, involve some measure of choice. We’ve marked these schools with an asterisk.
Illinois defines low-income students as being eligible to receive free or reduced-price lunches, living in substitute care, or coming from families receiving public aid.
The composite meets/exceeds score for each school is the percentage of students who meet or exceed standards in reading and math. A meets/exceeds score of 60 means 60 percent of the students at a school achieved at or above the minimum score set for meeting state standards.
Data from the Illinois School Report Card is collected by the state from school districts. Information for some charter networks in Chicago is reported as an overall average instead of individual schools. We supplemented that with information from Chicago for those schools and noted the differences by the way the schools were identified:
We excluded scores from alternative schools.
All the data, from the state and the city, can include uncorrected errors, incomplete information and in some cases outright omissions. At best, the information should be considered a fairly definitive snapshot in time.
Data is from Illinois and Chicago government agencies. This report will be updated periodically. If you see spot errors. please contact us.
Here are some specific problems we've found as well as adjustments we've made:
Design and data analysis by Daily Herald News Art Editor Tim Broderick. Thanks to Francisco X Gaytan PhD, MSW, Professor Bret Longman and Linda Lutton for their guidance on statistics and schools. Find all the data and files for this here.