Clearly defined criteria provide guardrails against gerrymandering and give redistricting commissions and the public a way to judge maps.
Criteria include federal requirements, best practices established by legal precedent, and specific measurable mapping standards. When these are not clearly defined, or if their priority order is not clearly established, commissions can focus on some aspects of mapping while ignoring others.
Redistricting will always require judgements and trade-offs. Well-defined priorities help avoid litigation and make accurate representation more attainable.
There are no standards codified in law for mapping congressional districts.
Based on legal precedent, a top federally required standard for all district maps is population equality. For congressional maps this has been interpreted as exact equivalence unless other priorities are applied consistently or required by state law. For state legislative districts, disparities of up to ten percent have been permitted. In effect, congressional exact equivalence (i.e. one person deviation) forces split precincts, wards and municipalities, while the much larger deviation at the state House and Senate level allows substantial space for distorted representation.
Another federal requirement is protection against minority vote dilution as expressed in the Voting Rights Act (VRA). Section 2 of the VRA protects voters from discrimination based on race, color, or membership in a language minority group. That means it’s illegal to pack minority voters into a single district or crack them across multiple districts to limit their influence within those districts.
Beyond these federal requirements, the Pennsylvania Constitution requires that state legislative districts:
When drawing maps for Pennsylvania, these requirements are often in conflict with one another since many municipal boundaries are not compact and some counties and municipalities are not contiguous.
In past decades these mapping requirements have been loosely applied, resulting in sprawling districts and far more split jurisdictions than needed.
Supported legislation would clarify and prioritize standards, based on extensive recommendations and testimony from experts, mappers and the Pennsylvania public.
The bill is written to make clear that some criteria are absolute necessities:
For some criteria the bill provides specific quantifiable limits, tailored to each map category (congressional, PA House or Senate):
Other criteria provide points of comparison based on respected forms of measurement which may change over time:
A final group of criteria is less easily defined and dependent on extensive public input:
Competitive districts are often not possible without trampling most other redistricting criteria. In Pennsylvania, requiring or prioritizing competitive districts would result in oddly shaped districts that divide multiple communities. If drawn according to other prioritized standards, regions that are balanced between both parties should yield competitive districts. In other regions, that will not be the case. If PA continues to have similar numbers of voters from both major parties, and if maps are drawn fairly, overall district plans will be highly competitive, even if individual districts are not.
Allocation of incarcerated persons
Other resources: Where Are the Lines Drawn? All About Redistricting, Loyola Law School