SB 1011 Utah Senate · 2025 First Special Session

Redistricting Standards

SB 1011 establishes statistical standards to evaluate Utah's congressional and legislative redistricting plans for partisan fairness. It requires the Utah Independent Redistricting Commission and Legislature to use ensemble analysis - simulating at least 4,000 possible district maps - to check if proposed plans show partisan bias. The bill defines key terms like "partisan bias test" and mandates that maps passing these statistical checks cannot be deemed to "unduly favor" any political party. This directly affects how district lines are drawn in Utah, aiming to prevent gerrymandering by requiring objective, data-driven compliance with fairness standards. The law amends existing redistricting statutes without appropriating new funds.
Bill status signed all 5 stages cleared
Introduction
Oct 2025
Committee Review
Senate Passage
Oct 2025
House Passage
Oct 2025
Signed into Law
Oct 2025
Introduced Oct 6, 2025 Signed Oct 6, 2025
Maddy AI version diff · 3 comparisons

What changed between versions

Substitute #2 Enrolled · 4 edits · Oct 6, 2025
MODERATE
The bill adds two new statistical tests to the redistricting standards: the 'mean-median difference test' and a stricter definition for 'unduly favor or disfavor.' These changes require that redistricting plans not only pass the existing partisan bias test but also pass this new mean-median test to be considered fair. Additionally, the date of the document's creation was updated from October 6 to October 5.
Scope change
The scope of the redistricting standards was expanded to include a new mathematical test for partisan symmetry.
DEFINITION

Added a new definition for 'mean-median difference test,' which requires a redistricting plan to stay within a 2% deviation of the mean vote share to pass.

REQUIREMENT

Modified the definition of 'unduly favor or disfavor' to explicitly require that a map fail the new mean-median difference test to be considered unfair.

Added the mean-median difference test as a mandatory component for judicial review of congressional redistricting plans.

TECHNICAL

Updated the timestamp at the bottom of the document from October 6 to October 5.

Floor votes

How they voted

This bill passed the Senate by voice vote (no roll call recorded).
Full legislative history

Actions timeline

Total actions
27
Key actions
4
Committee
0
Oct 6, 2025
Signed into law
Governor Signed
executive
Oct 6, 2025
Upper · Passed
Senate/ signed by President/ sent for enrolling
upper
Oct 6, 2025
Upper · Passed
House/ signed by Speaker/ returned to Senate
upper
Oct 6, 2025
Lower · Passed
House/ passed 3rd reading
lower
Oct 6, 2025
Introduced
House/ 1st reading (Introduced)
lower
Oct 6, 2025
Introduced
Senate/ 1st reading (Introduced)
upper
1 primary · 1 co-sponsor

Sponsors