About CivicDiff

CivicDiff answers one question: what was different about the U.S. federal government on one date compared with another?

How it works

Every office-holder, judge, and agency is stored as an interval, with a start date and an end date. Every law, executive order, ruling, and amendment is stored as a dated event. A comparison takes a snapshot of who held power on each date, compares the two snapshots, and lists the events in between.

A comparison works like a git diff. The first date is the government as that day began, and the second is the government as that day ended. Everything dated between them, including both dates, is in the change log. So a "Biden term" comparison (Jan 20, 2021 → Jan 19, 2025) starts with President Trump's government on the morning of the inauguration, ends with Biden's on his last full day, and counts the executive orders he signed on day one.

Methodology notes

• Congress: Only voting members are counted, so delegates and resident commissioners are excluded. Majority counts group independents with the party they caucus with.
• Judges: A judge counts as active from commission until taking senior status or leaving the bench. "D-appointed" and "R-appointed" describe the appointing president's party, not the judge's views.
• Laws: Every public law is listed from 1973 (the 93rd Congress) onward, from Wikipedia and Congress.gov. For earlier years only notable acts are recorded, from curated lists. Laws are classified automatically. Landmark laws come from a short curated list, notable laws have their own encyclopedia article, and ceremonial laws are namings and commemorations. Everything else is routine.
• Budget: Figures compare the fiscal years containing each date. Inflation adjustment uses OMB's GDP chained price index. A fiscal year still in progress falls back to the latest completed year.
• Executive orders: Federal Register coverage starts with EO 12890 (December 1993). "In force" counts orders that haven't been fully revoked or superseded.
• Agencies: Agency histories come from Wikidata and are less complete than other sections. Reorganizations, renamings, and mergers are hard to date precisely.

Neutrality

CivicDiff reports counts, names, and dates, and doesn't score or rank outcomes. Changes are shown as neutral deltas, and party colors only identify parties.

API

Every comparison is also available as JSON: /api/diff?a=2017-01-19&b=2021-01-19. See the API page.