POVERTY-ACHIEVEMENT INDEX:
A Daily Herald and WBEZ analysis of the link between poverty and school achievement



Viewing results by year and income range

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.

Click here to find all the stories in our Generations at Risk series.



Find your school

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 ...

  • Find the schools in your district.
  • Click the name of any school in the list to view interactive graphics with key statistics going back to 2004, the earliest year available.

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.

Elementary school's composite meets/exceeds score and percent of low-income and minority students

Elementary school's Poverty-Achievement Index score

High school's composite meets/exceeds score and percent of low-income and minority students

High school's Poverty-Achievement Index score





How we calculated the Poverty-Achievement Index

  • We took Illinois School Report Card results from 2004 to 2014.
  • For each year, we separated schools that reported ISAT results (elementary and middle schools) from high schools that reported PSAE results.
  • We separated elementary schools into 10 income ranges (0-9.9%, 10-19.9% ...) and high schools into eight ranges (0-12.4%, 12.5-25% ...).


  • Then we calculated the average composite meets/exceeds ISAT and PSAE scores for each income range in each year.

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.



Elementary school results

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.

Low income and elementary schools

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 results

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.

Percentage-point gap

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.

Low income and high schools

The correlation between scores and income levels for high schools is also strong.

Click here to view an interactive graphic of 2014 high schools and click here for the 2004 version.




Notes and clarifications

Click here to find all the data and files for this web app.

About the Poverty-Achievement Index

Our Poverty-Achievement Index is based on a statistical technique called a Z score that shows how far something is from an average.

about z scores.


Z scores and the normal curve

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.

How we used them

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.

When the curve isn't normal

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 rangesAvg. ISATMedian ISATH.S. income rangesAvg. PSAEMedian PSAE
0- 9.9%84.084.90 – 12.4%74.274.6
10-19.9%78.078.612.5 – 24.9%67.268.8
20-29.9%72.371.825 – 37.4%58.257.9
30-39.9%65.565.137.5 – 49.9%51.350.3
40-49.9%60.560.550 – 62.4%44.944.8
50-59.9%56.256.262.5 – 75%36.735.4
60-69.9%52.051.275 – 87.4%34.732.4
70-79.9%47.246.587.5 – 100%21.818.0
80-89.9%42.541.4
90-100%39.038.5


About the ISATs

The ISAT test changed in 2006.

  • In 2004 and 2005, grades 3, 5 and 8 took ISAT tests in reading and math, while grades 4 and 7 were tested in science. (PDF: Guide to the 2005 Illinois State Assessment, page 3. "In Spring 2005, students in grades 3, 5, and 8 took Illinois Standards Achievement Tests (ISAT) in reading and mathematics. Students in grades 4 and 7 took ISAT tests in science." )
  • Starting in 2006, a different ISAT test was given in grades 3 through 8. Questions were written by Harcourt Assessment, Inc., and Illinois teachers. New grading scales and minimum standards were introduced that resulted in higher meets/exceeds levels than in previous years but little actual improvement to students' scores.
    (PDF: Guide to the 2006 Illinois State Assessment, Page 5: "Starting with the 2005–2006 administration, the ISAT includes a combination of items produced by Harcourt Assessment, Inc., (Harcourt) and items written by Illinois teachers." And Page 6: "All ISAT scores are now expressed on a “vertical” or continuous scale across grades 3 through 8 in reading and mathematics, and in grades 4 and 7 in science. ... Because student scores will be reported on new scales, the numerical values of the cut scores representing proficiency levels need to change as well.") (PDF: University of Chicago 2011 study, Page 14, Figure 2: "Students with the same scores in fourth and ninth grade have different scores in seventh grade." And Chapter 3: "Test Score Trends in the Elementary/Middle Grades.")
To highlight the difference between the two tests, 2004 results are labeled as “pre-NCLB ISAT.” We’ve also highlighted scores starting in 2013, the year minimum standards were changed to more closely align with college-readiness and common core standards.

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.



Testing or lottery-based schools

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.



About the data

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:

  • Schools labeled only as CHARTER SCH were individual schools whose data is included in the state's report card.
  • CHARTER NET SCH is data for schools obtained from the Chicago Public Schools website and through a Freedom of Information Act request to CPS.

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:

  • 2005 data was substituted for missing or likely incomplete 2006 low-income figures for the following schools: Aspira Chtr-Ramirez Hs, CICS-Bucktown, CICS-Prarie, CICS-Wasthington Park, CICS-Basil, CICS-West Belden, Univ of Chgo Chtr-Nko, UNO Chtr-Paz and UNO Chtr-Tamayo.
  • 2007 low-income figures were substituted for missing or likely incomplete 2008 low-income data for the following schools: CICS-AVALON/So Shore and Shabazz Chtr-Dusable
  • Data for the following schools in the years noted was not included because of missing or incomplete tallies. 2006: Aspira Chtr-Haugan, CICS-Northtown, CICS-Wrightwood, Shabazz Chtr-Sizemore, Shabazz Chtr-Shabazz and Unv of Chgo chtr-Donoghue. 2008: Unv of Chgo Chtr-Woodlawn and Learn Chtr Butler.
  • Waukegan CUSD 60's percent low-income in 2013 and 2012 are likely too low, based on the numbers reported in 2011 and in 2014. 2014 percent low income values were used for 2013.
  • Academic centers that serve elementary students but are located in high schools do not report separate low-income values. Their low-income values reflect the entire school.
  • For West Chicago District 33, low income numbers for 2013 and 2014 are likely too low. When accurate numbers become available, their information will be updated.
  • The 2014 percent low-income numbers for Township H.S. District 214 are from the district.
  • The 2014 percent low-income number for Sparta Primary Attendance Center was likely misreported and the 2013 value was substituted. Edinburg Jr. High School's 2014 low-income numbers may be incorrect have not been included.
  • Some schools in McLean County USD 5 were missing 2014 ISAT results.

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.