Richest Counties in Illinois (2026)

Median Income versus Average Income: Which Should You Use?

We usually suggest using median income data – either instead of or in addition to – average income data as a true indicator of wealth. If you haven’t thought about median versus average since your last standardized test, you aren’t alone. Here’s what they are:

• average is the sum of a set of numbers divided by the count of numbers in the set
• median is the middle number in the set of numbers

Now let’s say you had the following simplified set of income data.

Household 1: $30,000
Household 2: $50,000
Household 3: $1,000,000

The average income for this set is $360,000. The outlier data point ($1,000,000) skews the average WAY up. Conversely, the average income would be skewed WAY down if someone had an income of $500. The median income for the same data set is $50,000. Outlier data doesn’t skew the median.

Most Business Owners Should Use Median Income

So most business owners should use the median income as a true indicator of wealth, because it provides a more accurate representation of a typical income, especially in areas with significant income disparity.

When Should You Use Average Income

If your target market is high-income households, the average income may be more relevant. This is because the average income can highlight the presence of a higher concentration of wealthy individuals, which is beneficial for luxury goods and services marketing. We’re using average income on this page because using the Census’s highest reported median value of $250,001 could result in multiple ties for the richest geography.

Why do so many cities have a median value of $250,001?

The Census' American Community Survey uses $250,000+ as a jam value for median income estimates to protect privacy, ensure data consistency, and simplify reporting. A "jam value" in survey data refers to a placeholder or default value used when actual data points are unavailable, incomplete, or exceed certain thresholds. We represent this jam value as $250,001 to make it easy for you to sort.