We included every top-rate or millionaire tax we could find, from 2004 on, for which both a pre-collection official estimate and a later collection figure (or official re-estimate) are published in a source we could open. Taxes with no published bracket-level collections (New Jersey 2018 and 2020, New York 2021) and New Jersey's 2004 tax (whose estimate we could not retrieve from a source) are excluded. Where one tax has several years, we include each year that has a matching estimate. The Massachusetts row includes both the Department of Revenue's forecast and the Tufts dynamic estimate, because the second is the only pre-enactment estimate in the set that cut revenue for behavioral responses.
Geography
California, Massachusetts, New York, Maryland, Oregon, Washington
Unit of observation
One estimate-vs-actual comparison for one tax and one revenue period
Update cadence
Ad hoc; updated when new collection figures are published
Curator
FactHub Research Team
Supporting files
Source snapshots, manifests, quality reports, documentation,
and other materials used to produce or review this release.
A ratio describes the forecast error; it does not separate behavioral responses from market and economic changes.
Robustness checks
Sensitivity analysis:Ratios, verified comparisons only.
Dropping the two comparisons with secondary-source values (Oregon; Multnomah FY2025) leaves 16, of which 11 are above the estimate and 5 below, with every 2008-09 recession comparison still below.
Forecast vs. actual
Each forecast beside the value later observed by a saved
analysis. FactHub computes the error as the actual value minus
the forecast; for a range, it is zero inside the range and
otherwise measured from the nearest bound.
Forecast
Forecast value
Actual
Error
Percent error
Source
Proposition 30 personal income tax revenue, FY2011-12
California Legislative Analyst's Office,
California Legislative Analyst's Office Approximate date: ballot analysis for the November 2004 election. Other state reports give a higher accrual-basis figure for FY2005-06.
Proposition 63 surcharge revenue, FY2006-07
California Legislative Analyst's Office,
+433 US dollars, millions
outside the forecast range; error from the nearest bound
+24.52%
Massachusetts Taxpayers Foundation Range presented at the FY2024 consensus revenue hearing; date is the bulletin reporting it. The budget capped use at $1 billion, which was not a forecast.
4% surtax revenue (dynamic estimate), 2023
Tufts Center for State Policy Analysis,
Tufts University Center for State Policy Analysis Approximate date (January 2022). Estimate is for calendar 2023; compared with FY2024, the first full fiscal year of collections. The static estimate was $2.1 billion.
High-income surcharge revenue, SFY2009-10
New York State Division of the Budget,
Oregon Legislative Revenue Office The outcome is a revised projection ('about two-thirds' of $504 million) reported by Oregon Business; Oregon Business also reported first-year preliminary collections of $130 million against $180 million projected (72%).
Preschool for All tax revenue, FY2022
Multnomah County,
Multnomah County Approximate date: the forecast in place for FY2022 (the county does not date it). Willamette Week reported the projection as $119 million.
Preschool for All tax revenue, FY2025
Multnomah County,
Metro (Portland regional government) Approximate date: the original adopted budget. Metro's updated Fall 2024 forecast ($323.1 million) was within 0.6% of actual.
Capital gains tax revenue (gross), FY2023 (tax year 2022)
Washington Department of Revenue,
Retrieved October 21, 2026. California state government publication. Facts and figures quoted; document linked, not hosted
Reliability:
Government.
Nonpartisan fiscal adviser to the California Legislature; prepares the official ballot-pamphlet fiscal estimates. The handout reproduces the ballot-analysis estimates by year.
Retrieved October 21, 2026. California state government publication. Facts and figures quoted; document linked
Reliability:
Government.
Official ballot analysis of Proposition 55 (2016). The $7 billion figure is the state budget's assumption, not a final tabulation.
Retrieved October 21, 2026. California state government publication. Facts and figures quoted; document linked
Reliability:
Government.
State commission overseeing Proposition 63 spending; figures drawn from Governor's Budget fund condition statements, cash basis. The live site blocks automated access, so we read the archived copy.
Retrieved October 21, 2026. Publication of a private nonprofit. Facts and figures quoted; document linked
Reliability:
Advocacy group.
Business-backed fiscal research group; it opposed the surtax campaign but here reports the official hearing projections in a table. The bulletin is dated January 30, 2023.
Retrieved October 21, 2026. Massachusetts state government publication. Facts and figures quoted; page linked
Reliability:
Government.
Official DOR press release of August 9, 2024, reporting the July 24, 2024 preliminary certification; later certifications may revise it.
Retrieved October 21, 2026. University publication. Facts and figures quoted; document linked
Reliability:
Academic.
Nonpartisan university policy center, January 2022. Its dynamic estimate cut revenue about 35% for avoidance (central income elasticity of 1) and migration.
Reliability:
News report.
Business magazine item of December 16, 2010, summarizing a Statesman Journal report on an LRO presentation; the LRO document itself was not found. The original page is offline, so we link the Internet Archive copy.
Retrieved October 21, 2026. News article. Facts quoted; page linked
Reliability:
News report.
Portland weekly reporting figures from the county's annual financial report, November 21, 2025; we did not read the county report itself.
Retrieved October 21, 2026. Washington state government publication. Facts and figures quoted; document linked
Reliability:
Government.
Multi-agency fiscal note for SSB 5096 (2021), revised June 22, 2021. Gross tax = Education Legacy Trust plus Common School Construction lines; the note's $442M state total also nets out a B&O tax credit.
Retrieved October 21, 2026. Washington state government publication. Facts and figures quoted; document linked
Reliability:
Government.
Fiscal note for ESSB 5813 (2025), dated May 5, 2025; assumes about 900 taxpayers and ERFC growth, with no behavioral adjustment stated.
Retrieved October 21, 2026. Publication of a private nonprofit. Facts quoted; page linked
Reliability:
Advocacy group.
Business-supported fiscal research nonprofit that generally opposes new taxes; here it reports a figure attributed to the state's Economic and Revenue Forecast Council.
Retrieved October 21, 2026. Working paper; abstract quoted. Facts quoted; paper linked
Reliability:
Peer-reviewed study.
Peer-reviewed study using California tax-return data; Rauh is a Hoover Institution fellow. Erosion is measured against the authors' no-response counterfactual.
Retrieved October 21, 2026. Working paper hosted by OPB. Facts quoted; paper linked
Reliability:
Academic.
Economists at UNH, the Yale Budget Lab and Reed College; not yet peer reviewed. The authors call their estimate likely an upper bound.
Retrieved October 21, 2026. Washington state government publication. Facts quoted; document linked
Reliability:
Government.
Multi-agency fiscal note for ESSB 6346 (2026) as passed; states that affected taxpayers do not reduce taxable income and applies a 4.71% AGI cut for reduced IRS enforcement.
Limitations and reproducibility
Reproducible from public sources: Every estimate and actual value was typed from the cited source; build_fva.js computes the ratios, counts and per-tax summaries and writes the CSV tables and results.json. Running node build_fva.js reproduces the published files byte for byte.
Estimates and actuals are not always on the same basis. Several actuals are later official estimates rather than final tabulations (California FY2011-12 to FY2016-17, New York SFY2009-10, Oregon 2009-11), and California Proposition 63 actuals are cash-basis receipts.
Ratios are nominal and compare one estimate with one outcome; they say nothing about why the outcome differed. In particular, a ratio above 1 does not show that taxpayers did not respond to the tax, and a ratio below 1 does not show that they did.
Estimators differ (legislative analysts, revenue departments, a university center, local budget offices), and some estimates were made shortly before collections (Massachusetts FY2024, Multnomah, Metro) while others were made before enactment.
The Oregon outcome is a revised projection reported second-hand by Oregon Business, and the Multnomah FY2025 figures come from Willamette Week; these rows are marked Unverified.
The set is small (18 comparisons, 10 taxes) and not a random sample; its timing is dominated by the 2008-09 recession and the 2012-2025 market expansion.
Some forecast dates are approximate (see each forecast's note).
