Principles for Mapmakers

Any map is a distillation. Every map must leave out something. Voting maps, especially, are expected to carve fairness out of a complex, multilayered reality of geography, population, and politics.

Minnesota’s district maps should be drawn to ensure that individual votes count equally and that communities are fairly represented. But they can be drawn with political intent—to amplify or diminish votes, win elections, and maintain power.

In recent Minnesota redistricting cycles, both parties have employed consultants, sophisticated data, and the latest mapping technologies to draft boundaries that produce the greatest political advantage without triggering a legal challenge.

In a state as large and diverse as Minnesota, no map can ensure absolute fairness. But the redistricting principles championed by Common Cause guide mapmakers away from favoring parties or incumbents.

Principles in Bill

Each mapping principle strives to produce a particular effect. In combination, principles may conflict with each other. HF 1605 takes this into account by specifying the priority in which they are applied. The bill also requires reports that document how each principle was applied, the methods of analysis used, and the outcomes that resulted.

This set of principles is summarized below in priority order. At the bottom of the list are several principles sometimes proposed that not included in the bill.

Prohibited information. “No plan shall be drawn to purposefully favor or disfavor a political party or candidate.” Certain types of certain types of political information (registered voters, party affiliation, voting history, and demographics) are prohibited from being used by the commission in its initial phase. However, the data may be used to test a plan’s compliance.

Priority of principles. “Redistricting commissioners … shall adhere to the [eight] principles when drawing congressional and legislative districts. Where it is not possible to fully comply with [all principles], a redistricting plan shall give priority to those principles in the order in which they are listed below.”

Population equality. “Congressional districts must be as nearly equal in population as practicable. Legislative districts must be substantially equal, the population of a district being within 1.5 percent of the ideal.”

Contiguity. “Each district must be contiguous, with boundaries having a shape allowing for easy travel throughout the district.” A district is contiguous when all its parts are connected.

Minority representation. “Each district must be drawn in compliance with all state and federal laws,” so that minorities have an equal opportunity to participate in the political process, influence the outcome of an election, and elect candidates of their choice. This principle helps ensure that districts are not drawn to dilute or otherwise diminish a citizen’s vote based on race, ethnicity, or language.

Communities of interest. This is a widely agreed-upon consideration, but perhaps the least measurable and most subjective of the principles. The bill language provides more explicit guidance for the mapmakers.

“District boundaries shall recognize identifiable communities of interest. A community of interest is a contiguous population sharing social and economic interests that should be included within a single district for purposes of the community’s effective and fair representation. Communities of interest include but are not limited to geographic areas where there are clearly recognizable similarities of social, cultural, ethnic, economic, or other interests.”

“Examples of shared interests are those common to an urban area, rural area, industrial area, or agricultural area, and those common to areas in which the people share similar living standards, have similar work opportunities, or have access to the same media of communication relevant to the election process.”

Political subdivisions. “Counties, cities, and municipalities should be preserved to the greatest extent possible and in compliance with the other principles to preserve rather than divide them among multiple districts.”

Minimizing division of localities helps promote unity. From counties to school districts, these subdivisions are very affected by their legislative boundaries and the subsequent representation at the state level. Excessive splits or carve-outs in drawing districts may be a sign of gerrymandering.

Incumbents. “The residence of incumbents shall not be taken into consideration in the development or approval of a proposed plan.”

Compactness. “Compactness must be measured and established by one or more statistical tests and [districts] must be compact.” Irregular, non-compact districts are often suspected of having been gerrymandered. However, compactness is less meaningful as a measure in sparsely populated areas compared to areas where the population is densely packed.

Partisan symmetry and bias. “A district must not be drawn in a manner that unduly favors or disfavors any political party. The commission shall use judicial standards and the best available scientific and statistical methods to assess whether a plan unduly favors or disfavors a political party.”

Three common statistical measures of partisan gerrymandering are: the efficiency gap, partisan bias, and the mean-median difference.

According to political mapping technology experts PlanScore, “all of these metrics are reliable when a state is competitive, but only the efficiency gap should be trusted when one party predominates in a state.” Or as the paper “Gerrymandering and Compactness: Implementation Flexibility and Abuse” states, “variables used to calculate compactness are complicated by reality.”

Numbering. This establishes a scheme for identifying each Congressional and state district by number.

Other principles. These principles are sometimes proposed in redistricting plans. Because they favor political considerations, they are not included in HF 1605.




Principles EXCLUDED FROM the bill

The following principles are sometimes proposed in redistricting plans. Because they favor political considerations, they have been excluded from the bill.

Preserving the Cores of Prior Districts and Protecting Incumbents.  These principles are closely related and, when used, are typically subordinated to other principles. They typically call for the cores of prior districts to be preserved “where that can be done in compliance with the preceding principles,” and allow the addresses of incumbents to be taken into account.

The rationale is that making incumbents run against each other in newly drawn districts disrupts the political process. Preserving the cores of districts is also considered to be less disruptive to the citizens living in those districts. But the counter-argument is that gerrymandered or inferior prior districts should not be maintained, and protecting incumbents  is not a voter priority.

Competition. “Districts should be drawn to encourage electoral competition where that can be done in compliance with the preceding principles.” A standard for measuring competitiveness is typically stated along with the principle.

Encouraging competitive races seems like a worthy goal. However, there are multiple reasons why a district may not be competitive, and judging competitiveness involves introducing partisan voting data into the process, which could also be used for incumbent protection purposes.

It’s also possible that competitive districts could produce more electioneering by bringing in outside money from interests not aligned with the interests of the district. Coarsened campaigns tend to reduce voter faith in the election process and governing in general.

For more on redistricting principles and comparisons with other states, see Loyola Law School’s All About Redistricting.

Background and Summary of the Redistricting Bill
Selecting Commission Members
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