The Illinois Constitution assigns the state the primary responsibility for financing public schools.
The state doesn't live up to that responsibility.
Not by a long shot.
In the 10 school years from 1996-97 through 2005-06, the state supplied just 29 percent of the money collected by all Illinois public schools.
With only three sources of funding -- state, federal and local government -- 29 percent can hardly meet anyone's definition of "primary."
In the property-rich suburbs, the state contribution is particularly paltry.
Over the past decade, the state contributed 16 percent of all the revenue collected by the 94 districts in the Daily Herald coverage area.
And that doesn't count the bond debt local school districts took on.
Critics of the state's funding system key in on the discrepancy between the demands of the state Constitution and what the state actually delivers.
They say the system creates inequalities among poor and wealthy districts.
Some areas generate enough property tax revenue to render the state contribution inconsequential.
Other areas operate with very little revenue beyond the state contribution.
Then there are the middle-class districts, which often fare worse than either.
"The way Illinois funds education is both unfair and inadequate," says a position paper by the bipartisan Chicago-based Center for Tax and Budget Accountability. "The end result; the state fails to give every school enough money to provide a quality education to all children."
The state does make an effort to level the playing field.
Wealthy areas get less state aid.
Poor areas get more.
Yet, inequalities remain, some exacerbated -- rather than eased -- by the state's attempt to take from the rich and give to the poor.
How it's figured
Every year, the legislature sets a baseline level considered necessary to educate each student in the state.
Last year, the baseline level was $5,164 per student.
The baseline figure is not the amount the state provides per student.
Rather, it's the minimum amount the state says all districts should be able to raise for each student.
Once the baseline figure is set, the state uses a complex formula with multiple variables to determine how much each district should be able to contribute and how much of what's left the state will cover.
The primary variable is property value. The greater the property value within a district, the bigger the slice of the whole local taxpayers will have to kick in.
Schools with high concentrations of poor students also receive poverty grants.
A separate calculation determines how much districts should get for specific purposes, such as special education, bilingual education, early childhood programs and transportation.
In theory, then, all districts should be assured of receiving the baseline amount.
Very poor districts and those with high concentrations of special-needs students should receive supplemental state money, in recognition of the fact that it costs more to educate students with certain challenges.
And very wealthy districts should be able to fend for themselves.
That's the theory.
Here's how it plays out in practice in three districts.
The state has determined property-rich Butler Elementary District 53 doesn't need much help from outside sources.
In 2005-06, the state equations assigned just $700 per student to this DuPage County district.
Still, District 53 collected a total of $18,314 per student, among the highest per-pupil totals in the state, mostly through local property taxes and student fees.
The robust revenue allowed the district to pay average teacher salaries of $67,256, about $10,500 more than the state average.
It also allowed the Oak Brook district to employ a teacher for every 14 students. At elementary schools statewide, the average student-to-teacher ratio was 19 to 1.
For District 53, then, the state contribution was incidental.
In fact, District 53 could have refused the state contribution altogether and still raked in more revenue per pupil than all but 32 of the state's 874 school districts.
In South suburban Ford Heights Elementary District 169, the state contribution was anything but incidental.
Like Oak Brook 53, Ford Heights 169 is an elementary school district.
That's about where the similarities end.
The student body at Ford Heights is 85 percent low-income.
The student body at Oak Brook is zero percent low-income.
Most stark is the difference between the value of property in Oak Brook and the value of property in Ford Heights.
The state calculation shows all the property within the Ford Heights school district was worth $44 million -- about $62,000 per student.
Oak Brook, home to million-dollar mansions and the upscale Oakbrook Center mall, has about $761 million worth of property within its borders -- or about $1.6 million per student.
To review: an Oak Brook student is backed by 26 times more property wealth than a student from Ford Heights.
Still, these two districts on very opposite ends of the wealth spectrum aren't so far apart when it comes to per-pupil revenue.
In 2005-06, Ford Heights collected a total of $17,719 per student, nearly as much as Oak Brook.
As a result, Ford Heights was able to pay its teachers about the state average and maintain significantly smaller class sizes than the average elementary district in Illinois.
State money, which accounted for about 45 percent of revenue in Ford Heights, made these class sizes and teacher salaries possible.
The state chipped in about $7,369 per kid in Ford Heights, about $6,699 more than it gave for each kid in Oak Brook 53.
So the state aid formula is a great equalizer.
It rights imbalances by taking into account poverty and property values.
It takes from the rich, gives to the poor, and everything evens out in the end.
About 50 miles north of Oak Brook is middle-class Lake Villa Elementary District 41.
Lake Villa was not wealthy enough to raise much local money, but too well off to qualify for much state money.
In determining its 2005-06 cut, the state listed the value of property in the Lake Villa district as $463 million -- $154,000 per student.
Each Lake Villa student, then, is backed by about one-tenth the property value of an Oak Brook student, but nearly 2½ times more than a Ford Heights student.
Given the extent to which the Illinois funding system relies on property taxes, it would figure that Lake Villa taxpayers had to kick in more than Ford Heights taxpayers but less than Oak Brook taxpayers.
And, given the intricacy of the state equations, it stands to reason that the three districts would wind up with roughly the same amounts per student.
In 2005-06, Lake Villa collected a total of just $8,468 per student.
That's nearly $10,000 less than Oak Brook raised.
It's $9,250 less per student than Ford Heights got.
And it's about a third less than the state average of $12,675 per pupil.
Ultimately, Lake Villa landed less because it didn't have more -- more property wealth to augment the state contribution, or more poor kids with special needs to draw additional state funds.
Lake Villa received $2,930 per student from the state, $4,400 less than Ford Heights.
The average teacher in Lake Villa makes $8,770 less than a Ford Heights teacher and contends with significantly larger classes.
Lake Villa isn't the only suburban districts in this squeeze.
Of the 94 Herald-area districts, 22 have property values per student that are less than $200,000.
The state contributed, on average, $2,326 per student to these districts in 2005-06.
Meanwhile, the state contributed $4,007 per kid to the remaining 603 districts statewide with property values per student under $200,000.
Suburban districts -- districts which generally have the highest cost of living in the state -- received half as much state aid as districts in other parts of the state with similar property wealth.
It's these types of inequalities that lead to charges that the state formulas are inherently -- and often haphazardly -- unjust.
But setting aside questions of fairness, it's indisputable that the way Illinois funds education places a greater burden on suburban property taxpayers.
• Next week: The local contribution.
Three sources of income keep public schools running: local, state and federal funding.
Federal money generally goes to districts with students who are poor or have special learning needs.
Most suburban districts don't have enough of these students to attract a sizable chunk of federal aid.
In the 2005-06 school year, just 12 area districts received more than 5 percent of their revenue from federal sources.
West Chicago District 33 received the most federal money per student, at $890. The district received 11 times that amount -- $9,812 -- from state and local sources.
Oak Brook District 53 received the least federal money, $48 per student. Its total per student was $18,314.