# Economic Security

Number and percentage of Illinois children birth through age 5 living in families with income at or above 200% of the federal poverty level (FPL). It is essential to understand the population of young children being served, and it is the state’s goal over time to reduce the percentage of families with young children living in poverty.

### Data Highlights

The five-year average percent of Illinois children age 5 and under living in families with income at or above 200% FPL from 2014 to 2018 was 60.27%, which is 4.16 percentage points higher than the national average. During that time, Alexander County had the lowest percentage at 20.51%, and Monroe County had the highest percentage at 84.30%.

### Methodology

Math Refresher: Calculating percentage change between a variable’s values in time t and in time t-1

#### What does this really mean?

1. Calculate the difference between the two values you are comparing.
2. Divide the difference by the original number. Then, multiply the result by 100. Note that we are not calculating a percent point change, but a percent change. If you wanted a percent point change you would simply subtract and find the difference.
3. A positive number indicates a percentage increase, while negative number indicates a percentage decrease.
4. Values can be:
• Natural numbers {1,2,3,…}
• Rational numbers {0.25, 0.37, 0.56, …}
• Percentage numbers (just another expression of rational numbers)

#### Example 1

Your son in high school got 64.24% and 74.24% in his mid-test and final test, respectively. What is the percentage difference between the two tests?

Short answer: His final test score is 10 percentage points higher than his mid-test score. This is an example of a percent point change.
Insightful answer: He made 15.6% improvement in his final. (Recall, calculation yields positive number that suggests a percentage increase). This is an example of a percent change.

#### Example 2

There were two defective guitars produced, out of a total of 100 guitars (hence, defect rate is 2%). Eddie Van Halen, as a production manager, has been trying to improve reliability. Now, there is one defective guitar produced, again, out of a total of 100 guitars (hence, defect rate is 1%). What is the difference in the defect rates?

Short answer: The difference in the defect rates is 1 percentage point. This is an example of a percent point change.

Insightful answer: Eddie Van Halen has helped to reduce the defect rates by 50%. (Recall, calculation yields negative number that suggests a percentage decrease). This is an example of a percent change.

Source of data: Data was gathered from the 2009 – 2016 ACS 5-year estimates.