Sources and methodology

Votes. House roll calls come from the House Clerk's XML records and Senate roll calls from Senate.gov XML. Each vote keeps its exact question, official result, required majority, and every member's choice as printed (for example Yea, Aye, Present, or a candidate's name in a Speaker election). Individual records are counted and compared with the official totals; any difference is flagged rather than corrected. A Vice President's tie-breaking vote is shown separately. Voice votes have no individual record.

Members and seats. Current seats and vacancies come from the official House and Senate rosters. Identifiers (Bioguide, Senate LIS, FEC candidate IDs) come from the public-domain unitedstates/congress-legislators crosswalk, checked against the official rosters on every sync. Members who left during the covered period keep their recorded votes. Party is shown as printed on each vote at the time of that vote.

Chamber layout. The House has no assigned seats; both chambers are drawn as schematics grouped by party, not as floor plans.

Bills. Official titles, sponsors, cosponsors (including withdrawals), actions, CRS summaries, and subjects come from the Congress.gov API, refreshed when Congress.gov reports an update. Bills with recorded votes are loaded first. Cloture, amendment, and procedural votes are never presented as final passage.

Campaign finance. A member is linked to an FEC candidate only when the candidate's office, state, district, and surname match the seat the member holds; other crosswalk IDs are listed with the reason they were not used. Totals are the FEC's two-year-period figures from the latest amended reports. The contributing-committee table uses itemized receipts on Form 3 lines 11B–11C, excludes memo entries, keeps the latest amendment of each transaction, and is labeled with its own processing date because the FEC itemizes recent reports later than it publishes totals. Campaign funds are not personal finances.

Lobbying context. LD-2 reports from 2025 onward are scanned for explicit bill citations (for example "H.R. 1" or "S.J.Res. 82"). The Congress is taken from the filing when stated, otherwise from the report year. A citation is matched only if the bill exists in Congress.gov records, was introduced on or before the day the report was posted, and any title written next to the number agrees with one of the bill's official, short, or popular titles. Report text is often carried over from an earlier Congress, where the same number belonged to a different bill; such citations are rejected rather than shown. Only the latest version of each report is used. A profile lists citations of bills the member sponsored, cosponsored, or voted on, with the cited passage. That is not evidence of contact, influence, or the client's position, and report-level amounts are never allocated to a bill or member. Campaign funds, personal transactions, and lobbying spending are kept separate and never combined.

Disclosed trades. Periodic transaction reports filed since January 1, 2025 come from the House Clerk's disclosure index and PDFs and from the Senate eFD system (whose usage agreement the project accepted; the law it quotes bars commercial use of these reports other than by news media). Electronic House PDFs are read from their table layout and checked against each report's own row markers; Senate reports are read from their pages. Paper filings are listed with a link but are not machine-readable. Each transaction is shown as filed: owner category, asset, transaction and notification dates, and the value band (or the exact amount a filer entered). House amendments are labeled per transaction (Amended or Deleted); for the Senate, a later amendment supersedes the earlier version of the same report. A report is linked to a member only when the seat or chamber held on the filing date and the name agree. ChamberLens does not estimate prices, returns, or holdings.

The President. The President, the Vice President and their terms come from unitedstates/congress-legislators; the offices are numbered by change of officeholder, as is customary. Official portraits come from Wikidata and are shown only when Wikimedia Commons marks the file public domain. Executive orders, proclamations, memoranda, notices and determinations come from the Federal Register API, with the Federal Register's own notes on what each document revokes or amends and what later revoked or amended it; documents appear there a few days after signing. Bills presented to the President, and whether each was signed, vetoed or became law without a signature, come from Congress.gov's Library of Congress actions. Nominations come from Congress.gov, limited to those received since the term began; status follows the latest action, and a confirmation links to the Senate vote its latest action names, or to the Senate's vote on the nomination. Financial disclosure reports (OGE Forms 278e and 278-T) are listed from the Office of Government Ethics and linked rather than read, because OGE posts them as scanned images; the same Ethics in Government Act limits on commercial use apply as to congressional reports.

Freshness. Sources are checked on a schedule (votes every few minutes on weekdays from 9:00 to midnight Eastern, less often otherwise; rosters daily). Faster checking cannot remove a publisher's own delay. A failed check never removes previously verified data. "No records found", "not yet ingested", and "source unavailable" are shown as different states.