The cost of living is higher in Chicago and its suburbs than elsewhere in the state. No secret there. And the fact that Lake County's property taxes are ranked 15th highest in the nation doesn't help matters.
Earlier this year, the Massachusetts Institute of Technology developed a living wage calculator, which approximates the income needed to meet a person's or family's basic needs in 2013. The calculator lumps the Chicago area into one region, so it produces the same numbers for Cook County and the suburbs.
According to the calculator, the living wage for an individual is $8.08 in downstate Rock Island County, nearly 30 percent lower than the $10.48 wage in the Chicago area. For a family of two adults and two children, the living wage is $17.68 in Rock Island and $20.35 in metropolitan Chicago.
Illinois' minimum wage is $8.25.
One of the biggest factors in the difference between the two regions is housing, which costs $790 a month for an individual in metro Chicago and $463 in Rock Island County, according to the calculator.
What the calculator doesn't point out is that income is higher in Chicago and its suburbs.
Based on Census numbers, the median household income is $48,205 in Rock Island and $79,085 in Lake County – a 35 percent difference.
MIT says its calculator is meant to provide one perspective on the cost of living in the United States.
"While the minimum wage sets an earnings threshold under which our society is not willing to let families slip, it fails to approximate the basic expenses of families in 2013," MIT's website says.
As a result, many working adults must seek public aid or hold multiple jobs to feed, clothe, house and provide medical care for their families, the site says.
Norm Walzer, a senior research scholar for Northern Illinois University's Center for Governmental Studies, said comparisons between regions can be hard. Discussions about the living wage, he said, are often political in nature.
Walzer said income tends to be greater in areas with higher costs of living. When large companies move its employees around, he said, they often take regional pay differences into account in setting wages.
A rise in the minimum wage, though, may not be the solution, he said. When the minimum is increased, employers find ways to do away with positions – sometimes by looking for more efficient ways to do things, he said.
"There aren't many people right at the minimum wage, but it's the base for other wages," Walzer said.
Christopher Marmé, an economics professor at Augustana College in Rock Island, said a minimum wage increase "sounds great at the ground level." In the short run, it may be hard to replace a beneficiary of a minimum wage increase.
"'We can't get rid of Mary,' a company says. 'We need someone to answer the phone.' But the company may figure that most of its correspondence is over email. Once Mary retires, the company might not replace her," Marmé said.
Regional differences in Illinois are obvious, he said.
"Downstate, you have a lower cost of living. People don't need to be paid as much to make ends meet."