John Katko

How this is assembled

• Roll calls come from the Senate's LIS XML (senate.gov/legislative/LIS/roll_call_votes) and the House Clerk's EVS XML (clerk.house.gov/evs), fetched nightly and never edited.
• The party line on a roll call is the majority among that party's yea and nay votes. Party unity is the share of this member's yea/nay votes that matched it; a break is a vote that did not. Votes of “present” and absences count toward attendance only.
• Members are identified by Biographical Directory (bioguide) id; senators' LIS ids are mapped through the unitedstates/congress-legislators roster.
• Floor speeches come from the Congressional Record (govinfo), split at the speaker lines the Record prints and matched to the member by surname, chamber and state; a passage that names a measure the member later voted on is paired with that vote. Trades are the member's own STOCK Act periodic transaction reports — House filings parsed from the Clerk's PDFs, Senate filings from the Senate's electronic disclosure system. A trade is flagged when its company's sector is one a committee the member sits on oversees, when the member cast a yea or nay on a measure in that sector within thirty days of the trade, or when PACs in that sector gave the member $10,000 or more in a cycle. Sectors for companies come from the SEC's company list and SIC codes; measures' policy areas from the Library of Congress via govinfo.
• Funding is the member's principal campaign committee as filed with the FEC: receipt totals from the committee's summary, every contribution from another political committee (Form 3, line 11C), and the FEC's own roll-up of individual money by employer. Sectors are assigned by a fixed, published list of name patterns, and the rule that fired is stored with each row.

A break with the party is a fact of the record, not a verdict. Procedural votes, amendments and motions to recommit are all in here; what a given break means is a question for the measure it was on, which is one click away.