About HAM
Housing Affordability Map — Methodology & Data Sources
Built by @calebosemobor
Hi, I'm Caleb. I built this project because I was curious to see what the data actually looked like, and I figured other people might be interested too. I have a background in private equity and corporate development. I graduated from Georgetown University with a double major in Accounting and Finance, plus a minor in music. HAM is a personal, data-driven project meant to give a clearer picture of how home prices compare to take-home pay across the U.S., using simple assumptions and transparent methodology.
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HAM (Housing Affordability Metric) is a ratio: home price divided by annual net income. A HAM of 6 means the median home costs 6 times the area's annual take-home pay. Higher numbers indicate a greater gap between home prices and local incomes.
HAM is calculated for every U.S. county to provide a granular, county-level view of the relationship between home prices and incomes across the country.
Why This Metric?
Existing housing affordability indices measure whether a median-income family can qualify for a mortgage at current interest rates. HAM asks a simpler question: how many years of your actual take-home pay does a home cost?
Three things make HAM different:
- It uses net income (take-home pay) instead of gross income
- It calculates affordability for minimum wage workers, not just median earners
- It covers every U.S. county individually rather than metro areas or national averages
HAM is not a mortgage qualification tool. It's a measure of the raw gap between what homes cost and what people earn.
Metric Definitions
Median HAM
Median Home Price / Net Median Individual Income
Ratio of the median home price to the typical income earner's net income in a county. A Median HAM of 5 means the median home costs 5 times the median worker's annual take-home pay.
Minimum HAM
Median Home Price / Net Annual Minimum Wage Income
Ratio of the median home price to a minimum wage worker's net income. A Minimum HAM of 15 means the median home costs 15 times a full-time minimum wage worker's annual take-home pay.
HAM Burden
(Monthly Rent / Monthly Net Minimum Wage Income) × 100
Percentage of a minimum wage worker's net income consumed by rent. A HAM Burden of 75% means three-quarters of take-home pay goes to rent alone.
Interpreting HAM Scores
Higher HAM scores indicate a greater gap between home prices and local incomes. The color scale shows relative standing across counties:
| HAM Score | Category |
|---|---|
< 4 | Low |
4 – 6 | Moderate |
6 – 10 | Elevated |
10 – 15 | High |
15+ | Very High |
Net Income Calculation
HAM uses net income (take-home pay), not gross income. Net income is calculated as:
- Federal tax: 2025 marginal brackets, single filer, standard deduction ($14,600)
- State income tax: State-specific flat or effective rates for all 50 states + DC
- FICA: 7.65% (6.2% Social Security + 1.45% Medicare)
Data Sources
| Data | Source | Frequency | Coverage |
|---|---|---|---|
| Home Prices | Zillow ZHVI | Monthly | ~2,500 counties |
| Home Prices | Redfin | Monthly | ~1,800 counties |
| Home Prices | Census ACS | Annual | All counties |
| Rent | Zillow ZORI | Monthly | ~1,500 counties |
| Income | Census ACS (B20017) | Annual | All counties |
| Min Wage | State labor departments | As changed | All states + DC |
Home price source priority: Zillow ZHVI > Redfin > Census ACS. Each county uses the best available source.
Assumptions & Limitations
- Filing status: Single filer with standard deduction. Married couples or those with dependents may see different results.
- Work hours: 2,080 hours/year (40 hours/week × 52 weeks) for minimum wage calculations.
- Income data lag: Census ACS income data has a ~2 year structural lag. The most recent available data may be from 2023 while home prices are from 2026.
- No local taxes: City/county income taxes are not yet included (affects cities like NYC, Philadelphia, etc.).
- No property tax or insurance: The HAM score measures the price-to-income ratio only, not the full cost of ownership.
- Rent coverage: Zillow ZORI covers only ~1,500 of ~3,200 counties. Rural counties may show no HAM Burden data.