What it measures
For most of its history the House called the roll aloud, name by name. On January 23, 1973 it held its first electronic vote, a 15-minute roll call; voice roll calls had typically taken 30 to 45 minutes. The Senate still calls its roll aloud. MS counts Not Voting ÷ recorded votes while seated; “Present” counts as answering.
By the numbers
| Measure | Value | Source |
|---|---|---|
| Share of each legislative day the House spent calling the roll, 1967–69 (Reading Clerks’ report) | 24% | History, Art & Archives, U.S. House |
| Members voting in the first House electronic vote, Jan 23, 1973 | 331 | History, Art & Archives, U.S. House |
| Median lifetime missed-vote rate, House members serving Dec 1970 | 8.5% | GovTrack |
| Same median, Dec 1974 | 9.7% | GovTrack |
| Same median, Dec 1982 | 7.8% | GovTrack |
| Same median, Mar 2025 | 2.1% | GovTrack |
| Senate median, any period | data needed | not yet sourced |
GovTrack publishes these medians on individual member pages; the figures are quoted from those pages. When the 218-member quorum first lit the new tally board in 1973, members in the chamber cheered (House History). Full formula: Methodology.