King County total homelessness rate vs. rent-predicted rate, all large CoCs
Question: How far is King County's total homelessness rate per 10,000 above or below the rate predicted from its median rent, across 59-66 large CoCs?
Result: 2015: +18.2 (95% PI -26.33 to 62.73); 2016: +20.41 (95% PI -26.65 to 67.48); 2017: +23.35 (95% PI -19.64 to 66.35); 2018: +23.06 (95% PI -18.35 to 64.47); 2019: +16.2 (95% PI -25.07 to 57.47); 2022: +25.87 (95% PI -13.35 to 65.09); 2024: +34.03 (95% PI -22.33 to 90.39)
Operation: Leave-one-out OLS of homelessness rate on median gross rent; King County residual with 95% prediction interval
Scope: All full-count CoCs in the 67-CoC sample, 2015-2024, King excluded from each fit
| Estimate | Value | Uncertainty | Method | n |
|---|---|---|---|---|
| 2015 King County total rate minus rent-predicted rate | 18.2 ± 22.29 per 10,000 residents (95% CI -26.33 to 62.73) | ± one standard error; 95% confidence interval | Leave-one-out OLS on median rent; 95% prediction interval | 66 |
| 2016 King County total rate minus rent-predicted rate | 20.41 ± 23.45 per 10,000 residents (95% CI -26.65 to 67.48) | ± one standard error; 95% confidence interval | Leave-one-out OLS on median rent; 95% prediction interval | 54 |
| 2017 King County total rate minus rent-predicted rate | 23.35 ± 21.52 per 10,000 residents (95% CI -19.64 to 66.35) | ± one standard error; 95% confidence interval | Leave-one-out OLS on median rent; 95% prediction interval | 66 |
| 2018 King County total rate minus rent-predicted rate | 23.06 ± 20.65 per 10,000 residents (95% CI -18.35 to 64.47) | ± one standard error; 95% confidence interval | Leave-one-out OLS on median rent; 95% prediction interval | 55 |
| 2019 King County total rate minus rent-predicted rate | 16.2 ± 20.66 per 10,000 residents (95% CI -25.07 to 57.47) | ± one standard error; 95% confidence interval | Leave-one-out OLS on median rent; 95% prediction interval | 66 |
| 2022 King County total rate minus rent-predicted rate | 25.87 ± 19.61 per 10,000 residents (95% CI -13.35 to 65.09) | ± one standard error; 95% confidence interval | Leave-one-out OLS on median rent; 95% prediction interval | 63 |
| 2024 King County total rate minus rent-predicted rate | 34.03 ± 28.14 per 10,000 residents (95% CI -22.33 to 90.39) | ± one standard error; 95% confidence interval | Leave-one-out OLS on median rent; 95% prediction interval | 59 |
- Rent alone explains little of the variation across large CoCs, so the prediction intervals are wide.
- King County switched to respondent-driven sampling in 2022; its 2022 and 2024 rates are not directly comparable with visual counts.
- Cross-sectional association within one year; not a causal estimate.
Robustness checks
- Alternative comparison: King County total rate vs. rent-predicted rate, HUD Major City CoCs only. Against HUD Major City CoCs only, King's residual is near zero through 2019 (-8 to +6) and +9 to +14 in 2022-2024. Every interval includes zero.
- Alternative comparison: King County total rate vs. rent-predicted rate, excluding New York City. Dropping New York City barely changes the result.
- Sensitivity analysis: King County 2024 total rate vs. rent, with count-method adjustment. Removing the estimated count-method premium (1,100 or 3,600 people) lowers the 2024 residual to +29 or +19 in the full sample and to +10 or -1 among Major City CoCs.
- Other check: King County unsheltered rate vs. rent-predicted rate, all large CoCs. For the unsheltered rate, King is above the prediction every year; the 2024 interval (+0.7 to +51) just excludes zero in the full sample but not among Major City CoCs.