economy_homeownership_finance_county_year
IRS SOI itemizing patterns and mortgage data (G2). Tier A- (itemizer-driven). History 1989-present at source; currently 2022 only.
tier a-composite_index
overview
overview
3,142 counties. Itemizer-only sample within IRS SOI.
current vintage — Tax Year 2022
history — IRS SOI: 1989 to present at source; pipeline loads 2022 only
provenance
source & licensing
authority
U.S. Internal Revenue Service
dataset
IRS Statistics of Income (SOI) County-Level Data — mortgage and homeownership
license
Public domain (U.S. Federal Government work)
citation
U.S. Internal Revenue Service. Statistics of Income (SOI), County-Level Data - mortgage interest and homeownership, Tax Year 2022.
schema
fields
| name | type | definition |
|---|---|---|
| country_idkey | string | ISO alpha-2 country code (always 'US' for domestic tables).Part of primary key. |
| county_idkey | string | 5-character FIPS code identifying the county.Part of primary key. Joins dim.counties on county_id. |
| county_name | string | Human-readable county name corresponding to county_id. |
| itemized_returns | int64 · count | Number of returns in which the filer elected to itemize deductions rather than take the standard deduction. Higher values indicate greater prevalence of homeownership-related deduction claims. |
| mortgage_interest_per_filer | float64 · dollars (nominal) | Average mortgage interest deducted per itemizing filer, derived from IRS SOI aggregate mortgage interest reported divided by itemized_returns. Higher values indicate greater average mortgage debt service among itemizers in the county. |
| pct_filers_itemizing | float64 · percent (0–100) | Share of total filers who itemized deductions, expressed as a percentage (itemized_returns / total_filers × 100). Higher values indicate a larger fraction of the filing population with deductible expenses such as mortgage interest or state and local taxes. |
| state_idkey | string | 2-character FIPS code identifying the state.Part of primary key. Joins dim.states on state_id. |
| tax_year | int64 | Tax year for which returns were filed, as reported in IRS Statistics of Income (SOI) county-level data. Matches the calendar year of income, not the filing year. |
| total_filers | int64 · count | Total number of individual income tax returns filed in the county for the tax year. Serves as the denominator for itemization rate calculations. |
relationships
joins
primary key
county_id, state_id, country_id, year
common joins
dim.geographies on county_id
economy_charitable_giving_county_year on (county_id, year)
housing_tenure_county_year on (county_id, year)
usage
how to use this table
method
Aggregated from individual Form 1040 + Schedule A by county FIPS. Mortgage interest from Schedule A line 8a. Itemizing rate = filers with Schedule A / total returns.
do not use for
Total mortgage interest paid (excludes non-itemizers); homeownership rate (use ACS B25003); pre-TCJA vs post-TCJA comparison without adjustment.
known issues
Post-TCJA (2018+) itemizing rate dropped from ~30% to ~10% - interpret with care.
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last updated · Jul 7, 2026