# Washington Monthly Motor-Vehicle-Theft Offenses, 2018-2025 **Status:** Research release 0.1 **Coverage:** January 2018 through December 2025 **Unit:** Reported motor-vehicle-theft offenses by calendar month **Principal source:** FBI Crime Data Explorer (CDE), Washington summarized offense endpoint **Reproducibility:** Fully reproducible from a retained API response and the included PowerShell transformation ## What this release is This release converts the FBI Crime Data Explorer's nested monthly response into a documented, analysis-ready table. It includes: - Washington reported motor-vehicle-theft offenses and clearances. - FBI-published Washington offense and clearance rates. - Washington population and estimated population coverage. - The corresponding United States series for comparison. - Exact effective dates and descriptions of Washington's major pursuit-law periods. - Annual validation summaries and a source manifest with file digests. This is a FactHub-curated dataset. It is not an official publication of the FBI, WASPC, WSP, WACIC, WATPA, OFM, or the Washington Legislature. ## Does the monthly dataset already exist? Substantially, yes. The FBI CDE summarized-data endpoint already publishes a complete 96-month Washington series for January 2018 through December 2025. It also supplies monthly population-coverage estimates, rates, clearances, a national comparison series, and source refresh metadata. What did not appear to exist as one obvious public download was the different WSP/WACIC series described as the number of vehicles actually reported stolen. Public WACIC material is fragmented: - WASPC published an exact 2021 county-by-month table and a January-March 2022 table. - WATPA annual reports publish annual totals and trend charts. - WASPC offers a custom statistical-data request for formats not already published. The FBI CDE offense series and WACIC stolen-vehicle series are not interchangeable. For example: - FBI CDE currently reports 35,662 Washington motor-vehicle-theft offenses for 2021. - The April 2022 WASPC release reports 31,032 vehicles stolen in WACIC for 2021. That difference is too large to treat as rounding. Possible contributors include different systems, counting units, submission timing, revisions, and offense-versus-vehicle definitions. FactHub should preserve both series under distinct names if it obtains the complete WACIC extract. ## How this supports the pursuit-law article The monthly table improves the article in five ways. ### 1. It establishes timing Annual totals hide whether a change began before or after a law. Monthly observations allow the article to compare the theft trajectory around: - July 25, 2021, when HB 1054's restrictions took effect. - May 3, 2023, when SB 5352 broadened authority for specified offenses. - June 6, 2024, when Initiative 2113 broadened authority again. Because all three changes occurred during a month, analysis should either model the exact intervention date or treat each effective month as a transition month. It should not classify the whole month as uniformly pre-law or post-law without a sensitivity check. ### 2. It shows whether Washington differed from the national pattern The dataset includes the national motor-vehicle-theft rate from the same FBI endpoint. This matters because pandemic disruption and the Kia/Hyundai theft wave affected many states. A Washington increase that mirrors the national curve is weaker evidence of a Washington-law effect than a clear Washington-specific break. The national series is a descriptive benchmark, not a sufficient control group. A stronger design should add comparison states selected before estimating policy effects. ### 3. It exposes reporting coverage The FBI response includes estimated population coverage for every month. Washington coverage is approximately 99% for most of 2018-2024 but falls to roughly 96% in the second half of 2025. Analysts can: - Flag lower-coverage months. - Run sensitivity checks that exclude months below a stated threshold. - Avoid interpreting lower reported counts as entirely behavioral when reporting coverage changed. ### 4. It enables transparent calculations An article can cite an exact dataset version and saved calculation for: - Monthly and 12-month rolling totals. - Pre/post descriptive averages. - Percentage changes. - Washington-to-national rate ratios. - Interrupted time-series estimates. - Alternative specifications that exclude transition months. ### 5. It prevents overclaiming The series can show temporal association. It cannot by itself establish that pursuit policy caused the rise or decline in theft. During the same period, Washington experienced: - Pandemic-era disruption. - The Kia/Hyundai immobilizer vulnerability and social-media amplification. - Changes in policing, staffing, prosecution, detention, and vehicle-theft task forces. - Changes in insurer and manufacturer responses. - Changes in reporting coverage and source revisions. The responsible article question is therefore not simply, "Did theft rise after HB 1054?" It is: > Did Washington's motor-vehicle-theft trajectory change around the pursuit-policy interventions by more than would be expected from its prior trend, national conditions, comparison states, reporting changes, and vehicle-make composition? ## Files ```text data/monthly.csv Analysis-ready 96-month Washington and United States series. data/annual-summary.csv Annual sums and coverage ranges used for validation. data/policy-periods.csv Exact pursuit-law effective dates and analysis cautions. data/policy-period-descriptives.csv Unadjusted descriptive averages using only full months in each legal period. source/fbi-cde-wa-mvt-2018-2025.json Retained source response used by this release. release-manifest.json Retrieval metadata, source refresh date, and artifact SHA-256 digests. scripts/build.ps1 Reproducible extraction and validation script. quality-report.md Definitions, checks, discrepancies, and limitations. source-audit.md Inventory of official public sources and their suitability. data-request-template.md Proposed request for the unpublished WASPC/WSP agency-month extract. ``` ## Build Windows PowerShell 5.1 or newer is sufficient; no additional packages are required. To rebuild from the retained source response: ```powershell powershell -ExecutionPolicy Bypass -File .\scripts\build.ps1 ``` To retrieve a new CDE response and rebuild: ```powershell powershell -ExecutionPolicy Bypass -File .\scripts\build.ps1 -Refresh ``` Refreshing the endpoint may change historical values. A refreshed result should be reviewed and released as a new immutable dataset version rather than replacing a published release. ## Principal source FBI Crime Data Explorer summarized endpoint: ```text https://cde.ucr.cjis.gov/LATEST/summarized/state/WA/motor-vehicle-theft?from=01-2018&to=12-2025 ``` The retained response reports: - Maximum UCR data date: September 2026. - UCR last refresh date: September 15, 2026. ## Additional official sources - Washington Statistical Analysis Center, NIBRS data: https://sac.ofm.wa.gov/national-incident-based-reporting-systemnibrs - WASPC statistics, reports, and custom data-request form: https://www.waspc.org/cjis-statistics---reports - WASPC April 2022 vehicle-theft release: https://www.waspc.org/assets/GTWO/ED_Updates/Vehicle%20Theft%20media%20release%20FINAL%20April%2013%202022.pdf - Washington OFM/UW vehicular-pursuit study: https://ofm.wa.gov/news-publications/vehicular-pursuits-in-washington-state/ - Current pursuit statute, RCW 10.116.060: https://app.leg.wa.gov/RCW/default.aspx?cite=10.116.060 ## Recommended next acquisition Request from WASPC or WSP a machine-readable WACIC extract with: - January 2018 through December 2025. - One row per agency, county, and calendar month. - Number of vehicles entered as stolen. - Number recovered. - Reporting status and revision date. - Agency and county identifiers. - Counting and deduplication rules. - A statewide total calculated from the same extract. The request should explicitly ask whether historical records are revised after recovery, duplicate entry, jurisdiction transfer, or late reporting. Until that extract is obtained, this release should be cited as the FBI reported-offense series, not as the number of unique vehicles stolen.