Finding DORI: Using Item Response Theory to Measure Difficulty of Registration in the U.S. and Its Impact on Voters

• Date: 01 May 2022
• Published date: 01 May 2022
• DOI: 10.1177/1532673X211055050
• Subject Matter: Articles

Article

American Politics Research

2022, Vol. 50(3) 336–352

© The Author(s) 2021

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DOI: 10.1177/1532673X211055050

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Finding DORI: Using Item Response Theory

to Measure Difficulty of Registration in the

U.S. and Its Impact on Voters

Joshua M. Jansa, Matthew Motta, and Rebekah Herrick 

Abstract

How do states differ in how difficult they make voter registration, and what effect does this have on voters? We propose and

validate a new Difficulty of Registration Index (DORI) calculated via an item response theory (IRT) model of five key dimens ions

of registration (automaticity, portability, deadline, mode, and preregistration) for each state from 2004 to 2020. Since 2004,

most states eased registration processes, with Democratic statehouses in racially diverse and young states leading the way.

Using CCES data, we find that DORI is associated with increased probability that voters expe rience problems registering and

failing to turnout (in both self-reported and validated turnout data). These effects are pronounced for young voters. This study

holds lessons for how restrictive registration procedures can change the shape of the electorate and make it harder to achieve

political equality.

Keywords

Voter registration, youth turnout, state politics, item response theory, election laws

How do states differ in the difficultly of voter registration

procedures, and what effect does this have on voters? Extant

research typically examines the effect of specificregistration

dimensionson turnout, such as preregistration (e.g.,Holbein &

Hillygus, 2016), deadlines (e.g., Grumbach & Hill, 2020), or

portability (e.g., McDonald, 2008), or examines the overall

costs of voting on turnout,which does not distinguish between

registrationand voting procedures (e.g., Juelich& Coll, 2020).

Indeed, when scholars have attempted to measure registration

difficulty, they have typicallydone so with indices that include

both registration and voting laws (e.g., Li, Pomante, and

Schraufnagel 2018;Hill & Leighley, 1999;King, 1994).

While these approaches have substantially advanced our un-

derstanding of voterregistration in the US, insights from these

studies may be limited by either their treatment of registration

laws in isolation or their inability to separate the effect of

registration difficulty from voting difficulty.

Measuring the overall level of registration difficulty in

each state and over time is critically important for under-

standing voter turnout, particularly among young voters. We

know from the foundational works of Downs (1957) and

Riker and Ordeshook (1968) that higher costs of voting, or

how much time and resources one must commit to suc-

cessfully voting, should depress voter turnout. Registration is

a costly step in the process of voting that falls dispropor-

tionally on the young, as they are most likely to be new voters

or voters who have recently moved (e.g., Wol finger &

Rosenstone, 1980). Confusing or difficult procedures can

create registration problems for young voters; indeed, Mil-

lennials are more likely to report registration problems than

other generations (CCES, 2018). Since voting is habitual,

creating confusion for young voters could turn them off from

participating for their lifetime and can distort the electorate

(Plutzer, 2002;Coppock & Green, 2016;Fowler, 2017). In

competitive elections, such as the 2016 presidential election

where the outcome was determined by a fraction of voters in a

handful of states, or the 2020 Iowa second congressional race

where just 6 votes separated the winning and losing candi-

dates, any number of voters being turned away have the

potential to change election outcomes.

To examine the effect of registration procedures on voters,

we create a Difficulty of Registration Index (DORI) using a

hybrid item response theory (IRT) model for five major di-

mensions of registration—automaticity, deadline, mode,

portability, and preregistration. These dimensions govern if

Oklahoma State University, Stillwater, OK, USA

Corresponding Author:

Joshua M. Jansa, Oklahoma State University, 233 Social Sciences and

Humanities Bldg, Stillwater, OK 74074, USA.

Email: joshua.jansa@okstate.edu

an eligible voter must take action to register, when and how

an eligible voter can register, whether the registration is valid

across the state rather than a specific domicile, and whether

registration is available to voters who are currently underage.

These standards are well-established in the literature as key

dimensions of registration procedures. The IRT approach

allows us to take into account the unique contribution of each

dimension to the overall difficulty of registration procedures

in each state and over time.

This approach gives us leverage on variation across the

states in registrationdifficulty and how stateswith higher levels

of difficulty can cause problems for voters that prevent them

from casting a ballot.We first identify the major dimensions of

registration laws across the states and then describe how we

use these dimensions to create DORI scores for each state

using IRT. Wethen show how DORI scores have changedover

time, with many sta tes making registration eas ier since 2004.

Wevalidate DORI by assessing itsstate-level correlates and by

comparing its predictive performance to an additive index of

registrationlaws. We use DORIto explore the consequences of

registration difficulty for voters. We find that voters in states

with higherDORI scores are more likely to report experiencing

problems registering to vote, and are less likely to vote as a

result. Troublingly, we find that these effects are most pro-

nounced for youngvoters. In all, the creation of DORIand our

demonstration of its impact on voters provide a new tool for

studying voter registration in the U.S. federal system and its

electoral impact.

Five Dimensions of Voter Registration

Procedures in the States

In the U.S. federal system, voter registration laws are mostly

determined by state governments. National laws such as the

Voting Rights Act of 1964 (VRA), the National Voter

Registration Act of 1993 (NVRA), and the Help America

Vote Act of 2002 (HAVA) create basic voting and registrat ion

regulations across the U.S., but state prerogatives have

created significant spatial and temporal variation in five

parameters, or dimensions, of voter registration laws. These

dimensions are automaticity (i.e., whether action is required

for voters to become registered), mode (i.e., how a state

allows voters to register), deadline (i.e., whether and when

voters must be registered before election day), portability

(i.e., whether voters’registration is honored state-wide), and

preregistration (i.e., whether registration procedures are

available to otherwise eligible voters who are underage).

We identified these five dimensions after a review of the

extant research. Our goal was to identify the major dime n-

sions of registration procedures and then to use this infor-

mation to create a single measure of registration difficulty in

each state over time. We used two criteria to determine what

constitutes an important dimension of voter registration law.

First, the dimension and the underlying laws that shape it

must be primarily focused on registration procedures and not

on determining votingprocedures, including who is eligibleto

vote. Second, it must shape the steps that individual voters

must take to fullyregister, and not governhow organizations or

political parties that may seek to register voters.

1

Although

these dimensions do not capture all possible voter registration

laws, scholars focus on these dimensions above all others in

determining how difficult it is for an eligible individual to

registerto vote (Leighley & Nagler,2014;Holbein & Hillygus,

2016;Fowler, 2017;Yu, 2 01 9). Below, we define each di-

mension andsummarize its importance for shapingregistration

costs for individual voters.

Automaticity

Whether action is required for voters to become registered is a

key dimension that varies across the states. As of 2020, eighteen

states

2

had instituted mechanisms for automatically registering

eligible citizens to vote (NCSL, 2019a). These AVR provisions

allow state agencies to share with election administrators the

basic information they gather from eligible citizens. Election

administrators use the information to create or update voter

registration records. In this way, voters are registered without

having to spend time and resources completing the specific

actions required to become registered.AVRisthusviewedasa

waytoreducethecostsofvoting(Li et al., 2018). AVR is a

relatively new innovation, so few comprehensive studies have

been conducted on their effect, though McGhee and Romero

(2020) find that AVR laws greatly increases the voter registration

rates among Latinos, and modestly increase voter registration

rates among Asian Americans and young people as well.

Mode

The mode dimension captures how a state allows a voter to

register. All states—whether due to the NVRA or by their

own regulations—have paper voter registration forms that

can be submitted in-person or by mail. Arizona was the first

state to allow voters to register online in 2002. By 2020, 40

states had enacted online voter registration (OVR), while 10

states kept paper-only procedures (NCSL, 2019b). OVR is a

popular mode of registration because it makes registration

accessible on laptops or mobile devices, and it decreases

administrative costs to the states (Hicks et al., 2016). OVR is

associated with increased turnout especially among young

voters (Yu, 2019).

Deadline

Whether and when voters must be registered before election

day is another key dimension of variation in registration laws

across the American states. Some states require registration to

be completed before election day, typically 10–30 days prior.

Most states’deadlines have not changed over time, though

many states have begun adopting election day registration

Jansa et al. 337