Do car diagnostic problems track median household income across states?
Across U.S. states, NHTSA owner complaints about car diagnostic run higher where median household income is higher, after adjusting for the makes sold in each state. This is an association across states, not proof that median household income causes this repair.
State reports of this repair against median household income, one dot per stateEach dot is a state: how much more (or less) than expected this repair is reported there, adjusted for the makes sold in the state, against its median household income (dollars)
How to read it: Each dot is a state. Further right means more median household income (dollars); higher up means more complaints for this repair than expected (1.0 is average). If the dots climb to the right, reports of this repair rise with median household income (dollars).
What it shows: States with more median household income (dollars) tend to sit higher on the chart across 51 states: a pattern in the data, not proof of cause.
Data: U.S. Census Bureau, American Community Survey 5-year 2019-2023 (B19013), joined to NHTSA owner complaints, downloaded 2026-10-06 · 51 states. Chart: CalcScrape · calcscrape.com
The 10 states with the most median household income (District of Columbia, Maryland, Massachusetts, New Jersey, Hawaii, California, New Hampshire, Washington, Connecticut, Colorado): reports of this repair run 7% above what the makes sold there would predict, and 7 of 10 are above expected. The 10 with the least (Mississippi, West Virginia, Arkansas, Louisiana, Alabama, New Mexico, Kentucky, Oklahoma, South Carolina, Tennessee): 3% below, and 2 of 10 are above expected.
Exceptions: Massachusetts, New Hampshire and Washington are among the highest in median household income but report below expected; South Carolina (20% above expected) is among the lowest but above expected.
Split the states into thirds: the third with the least median household income runs 2% below what the makes sold there would predict, the middle third 1% above, and the third with the most 4% above. It steps up steadily.
For median household income, after allowing for the 1562 comparisons we ran, luck alone would produce a pattern this strong about 1 time in 7. The median household income pattern leans on Hawaii: without it, it weakens.
Weak spot: compare only states with similar cost of living index and the pattern keeps about 0% of its strength, so part of it may come from cost of living index instead of median household income.
Lower income means older cars kept longer and repairs put off until a part fails, which changes which repairs owners report.