CUE Research · Study 12
Every Member of the U.S. Congress
More than twelve thousand senators and representatives since 1789: the largest study CUE has run.
The question: Across twelve thousand lawmakers, do any numbers, signs or birthdays appear more often than chance?
What stands out
- Clear difference · Birth quarter
Every member: Jan–Mar appears 3232 times against about 2981.5 expected (1.08×).
- Clear difference · Birth quarter
Representatives: Jan–Mar appears 2737 times against about 2513.5 expected (1.09×).
- Clear difference · Birth quarter
Every member: Apr–Jun appears only 2780 times against about 3006.1 expected.
- Clear difference · Chinese sign
Born since 1950: Dragon appears 130 times against about 94.3 expected (1.38×).
- Clear difference · Birth quarter
Representatives: Apr–Jun appears only 2375 times against about 2534.3 expected.
- Clear difference · Birth month
Every member: Feb appears 1038 times against about 933.4 expected (1.11×).
- Clear difference · Birth quarter
Senators: Apr–Jun appears only 405 times against about 471.9 expected.
Worth watching, not enough to claim
- Birth month
Every member: Jul appears only 918 times against about 1024.1 expected.
- Birth quarter
Republicans: Jan–Mar appears 1349 times against about 1245.9 expected (1.08×).
- Birth quarter
Republicans: Apr–Jun appears only 1155 times against about 1256.1 expected.
- Sun sign
Every member: Cancer appears only 955 times against about 1057.1 expected.
- Birth month
Representatives: Feb appears 874 times against about 786.8 expected (1.11×).
- Sun sign
Every member: Gemini appears only 927 times against about 1024.1 expected.
Every member: Jan–Mar appears 3232 times against about 2981.5 expected. That is a clear difference for a group of 12066.
Context What explains it
Before 1900, births in the United States were not spread evenly through the year: they peaked in late winter and early spring. The baseline assumes an even spread, so part of the early-year excess here reflects when babies were born at the time, not who went to Congress.
With twelve thousand people, even small differences can be detected. That cuts both ways: a real but tiny effect can show up as clear, so the study reports how big each difference is, not just whether it is there.
Members were born over nearly three centuries, and each group’s baseline uses its own birth years.
Source The data
- Members of the U.S. Congress, 1789–today. Retrieved 2026-09-28. View source
- Every senator and representative in the Biographical Directory of the United States Congress, via the congress-legislators project. Each member is listed once, under the chamber and party of their most recent term.
- Verification: 12066 of 12770 included. A member is included when the congressional record and Wikidata (matched by Bioguide ID) agree on the birth date to the day.
- Expected values: every day of the years each group was born in, weighted by how many people were born in each year, run through CUE’s engine. Weighting matters for Chinese signs and Life Paths, which depend on the year.
- A difference is called clear only in groups of 50 or more and at least three standard errors from expected. Because each study tests about a hundred values, a clear difference needs 3.5 standard errors; 2.5 to 3.5 is only “worth watching”.
Reproduce it: the raw data snapshots and build scripts are in CUE’s code repository (scripts/data and scripts/build-*-study.mts).
Further reading
- Biographical Directory of the United States Congress
- congress-legislators project (github.com/unitedstates/congress-legislators)