Methodology

Story dates

The date on a story is the date the development first became public — the release date of an IRS document, the signing date of a law, the day a court published an opinion, the first report by a news organisation. The outlet that first reported it is credited at the top of the source list.

Tables

Limits and brackets come from IRS revenue procedures and notices; state figures from state revenue departments and the Tax Foundation; deadlines from IRS publications. Each table names its sources and the date it was last checked.

Videos

Videos are third-party explainers selected for clarity and relevance and published no later than three days after the story date. They are not endorsements.