Does enumerating undocumented residents in the U.S. census affect congressional apportionment?
Level 4 - case-series / case-control
Level 4 by non-clinical design analogy (retrospective counterfactual demographic simulation using historical state estimates).
OpenAlex W4406915040 · doi:10.1093/pnasnexus/pgaf021
What was done
The authors evaluated whether enumerating undocumented residents in the United States census alters political party representation in the House of Representatives or presidential Electoral College votes. Using annual state-level estimates of undocumented resident populations at each census date from 1980 onward, they modeled counterfactual congressional apportionment outcomes had undocumented residents been entirely excluded.
What was found
Excluding undocumented residents from census apportionment data since 1980 would have shifted no more than two House seats and three Electoral College votes between political parties in any census year. These shifts would have had zero effect on party control of the House of Representatives or the outcomes of presidential elections.
Why it matters
This study directly quantifies the partisan impact of counting undocumented residents in the decennial census, showing that historical shifts would have been minimal and insufficient to alter national political power or presidential outcomes.
Limits
The study relies on state-level estimates of the undocumented population rather than exact administrative counts, which introduces estimation uncertainty. The abstract does not report exact margins of error, specific state-by-state seat changes, or the potential impact on internal state legislative redistricting.
Cited by
- supports The United States Census counts all residents rather than only citizens for the purposes of apportioning congressional seats.