redistricting gis map urban area

A digital elevation model of an urban area made with geographic information system software. If GIS is available to election officials, errors in assigning candidates and voters to correct precincts (and thus to correct districts) decline.

’Tis the Season to Redistrict: Two Pros Offer Insight

By Wendy Underhill | Dec. 20, 2021 | State Legislatures News | Print

As of mid-December, 21 states had enacted their congressional maps, 25 had enacted their legislative maps, and five states were in special sessions for redistricting. All were on track to have new districts ready to use in the 2022 primaries, pending litigation.

Since redistricting—the once-a-decade redrawing of electoral districts—is always a scramble and often a battle, it’s understandable that legislators might want to take a nice, long break after they’re done. Yet the best time to take stock of lessons learned is while memories are fresh. Future redistricters will thank you.

Since redistricting—the once-a-decade redrawing of electoral districts—is always a scramble and often a battle, it’s understandable that legislators might want to take a nice, long break after they’re done.

With that in mind, NCSL hosted a webinar, Redistricting Roundup, on Dec. 3. Michelle Davis, a senior policy analyst with the nonpartisan Maryland Department of Legislative Services, gave the lowdown on state and court actions. Then two stalwart redistricting professionals, Republican Clark Bensen and Democrat Kim Brace, shared procedural changes they agree could be helpful come 2031. Some of these ideas will help with elections throughout the decade as well:

Ensure all absentee and provisional ballots are attributed to the voter’s home precinct. When elections were held in physical polling places on one special day, election results were almost by definition accurate at the precinct level. Back then, the tiny number of absentee/mail ballots and provisional ballots didn’t much matter, so jurisdictions tallied them centrally. Now? With far more voters casting ballots outside traditional polling places, how those votes are recorded matters. It’s not about winners and losers—outcomes are fine either way. It matters for candidates, because they need to know where their likely voters live so they can campaign efficiently, and it matters for redistricters because they need to see the political makeup of the electorate through a geographic lens. States could legislatively mandate that all ballots be reported at the precinct level, but they’ll need to know that there is an added cost for printing and processing ballots with the necessary codes, which local jurisdictions will no doubt mention. (This is Brace’s No. 1 request from states.)

Tabulate all ballots by how they were cast. The ways we vote have expanded over the decades, and now—especially with a new partisan divide over whether to vote in person or by mail—inquiring minds want to know what method of casting a ballot suits their voters best. Politics watchers now (and redistricters later) will want information not just on who won, but also the results by each method of voting: in person on Election Day, in person during early voting, by an absentee/mail ballot, through special procedures for overseas voters, and by provisional ballots. State and local election officials may want to weigh in on what works and what costs are involved.

Work with the U.S. Census Bureau to improve data accuracy. At least twice during the decade, the Census Bureau asks states to lend a hand. In the mid-2020s, the Block Boundary Suggestion Project will give states a chance to suggest better census block boundaries. Prisons, in particular, are best kept to their own block and not combined with surrounding neighborhoods. But it’s also possible to tidy up edges where riverbanks are imprecisely mapped, new highways have been added or jurisdictional boundaries have changed. Something like two-thirds of the states participated in 2015 and ’16; there’s room for growth.

Every decade, the Local Update of Census Addresses Operation gets going in the year ending in numeral 8. LUCA, as the operation is known, gives states, tribes and local jurisdictions a chance to clean up the list of addresses the bureau will use when it’s showtime in 2030. While the census is a federal project, LUCA is a crowd-sourced, accuracy-improving program. Could a law be written to require the state’s census liaison to participate? Maybe.

Build in a statutory contingency plan to fix technical errors in maps. Any experienced redistricter will agree that mistakes happen. Spelling out in statute how technical errors can be corrected without having to open up redistricting again and introduce a new bill makes sense. (See page 152 in Redistricting Law 2020 for examples from states that have permitted the secretary of state or others to resolve ambiguities or errors.)

Define districts with block equivalency files. It used to be that metes and bounds were used to describe geography of all sorts. Now, geographic information systems can easily produce more accurate maps. But GIS-produced “shape files” are not infallible. Best practice? Our duo recommends block equivalency files that list every census block in the state and the districts assigned to it. That way, no geography is inadvertently left out or misassigned. (See page 151 for more on this.) GIS software isn’t strictly necessary for all census-related research—but it helps. In fact …

Do use GIS—and encourage your state’s election officials to do the same. All states use GIS to draw their maps, but once the maps are handed off to election officials, they are often translated back into address list files. If GIS is available to election officials, errors in assigning candidates and voters to correct precincts (and thus to correct districts) decline. This may be the nonpartisan election administration issue of the 2020s.

Collect data, frequently and completely.

  • Make election results centrally available in the state. Election results are key to redistricting. Bensen and Brace used to travel county to county to get results, and they are grateful that many states now have repositories of election results. Some states, such as Indiana, assign this responsibility to nonpartisan legislative offices that support redistricting when the time comes. If there isn’t a repository, then in the year ending in numeral 9, staff will scramble—and pay top dollar to consultants like Bensen and Brace to create an adequate database for redistricting. Much better to maintain records consistently, they say.
  • Keep copies of statewide voter registration databases for each election. Understandably, election officials are way more interested in who their current voters are than who their former voters were, so they often don’t keep archives of older voter registration databases. But redistricters will want them, so lawmakers could introduce legislation requiring an archive be kept, along with election results. Bensen says it would be ideal to have two snapshots: one capturing who was registered to vote on Election Day, and another taken after voter history—the record of whether the voter participated in an election—is added to the file.
  • Save precinct maps throughout the decade. Precincts are changed often throughout the years as areas grow or election policies change. When it’s time to look back at past election results to know who voted where in previous elections, the older maps are essential. Could this be part of the state repository? Maybe.
  • Include counts of registered voters and ballots cast by precinct for each election. Lastly, while data is being saved, it helps to include both the number of registered voters in each precinct and the number of votes cast in each as well. “This sometimes elusive information can be very useful for several analyses,” Bensen said, pointing particularly to work relating to voting rights laws such as racially polarized bloc voting analyses.

Wendy Underhill directs NCSL’s Elections and Redistricting Program.

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