AP VoteCast, United States, 2018 (ICPSR 37677)
Version Date: Jun 15, 2020 View help for published
Principal Investigator(s): View help for Principal Investigator(s)
Trevor Tompson, National Opinion Research Center;
Jennifer Benz, National Opinion Research Center
Series:
https://doi.org/10.3886/ICPSR37677.v1
Version V1
Summary View help for Summary
AP VoteCast is a survey of the American electorate conducted in all 50 states by NORC at the University of Chicago for the Associated Press (AP) and Fox News. The survey is funded by AP. The survey of 138,929 registered voters was conducted October 29 to November 6, 2018, concluding as polls closed on Election Day. Interviews were conducted via phone and web, with 11,059 completing by phone and 127,870 completing by web.
AP VoteCast combines interviews with a random sample of registered voters drawn from state voter files; with self-identified registered voters conducted using NORC's probability-based AmeriSpeak® panel, which is designed to be representative of the U.S. population; and with self-identified registered voters selected from nonprobability online panels. Interviews were conducted in English and Spanish. Respondents received a small monetary incentive for completing the survey. Participants selected from state voter files were contacted by phone and mail, and had the opportunity to take the survey by phone or online.
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Funding View help for Funding
Subject Terms View help for Subject Terms
Geographic Coverage View help for Geographic Coverage
Smallest Geographic Unit View help for Smallest Geographic Unit
State
Distributor(s) View help for Distributor(s)
Time Period(s) View help for Time Period(s)
Date of Collection View help for Date of Collection
Data Collection Notes View help for Data Collection Notes
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VoteCast National Survey: The VoteCast survey of voters and nonvoters nationwide is compiled from results of the 50 state-based surveys and a nationally representative survey of 4,913 registered voters conducted on the probability-based AmeriSpeak panel (4,413 completed online and 500 via phone). It includes 40,692 probability interviews completed online (30,133) and via telephone (10,559), and 93,324 nonprobability interviews completed online. The margin of sampling error is plus or minus 0.8 percentage points for voters (n=116,792) and 1.8 percentage points for nonvoters (n=22,137). Registered voters in the District of Columbia were not included. The overall response rate for the probability sample drawn from the state voter files was 4.2 percent.
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VoteCast State Surveys: In 25 states, VoteCast is based on roughly 1,000 probability-based interviews conducted online and via phone, and roughly 3,000 nonprobability intervews conducted online. In these states, the margin of sampling error is estimated to be plus or minus 3.5 percentage points for voters and 8.8 percentage points for nonvoters.
In 25 additional states, VoteCast is based on between 475 and 1,000 nonprobability interviews conducted online. In these states, the margin of sampling error is estimated to be plus or minus 8.7 percentage points for voters and 19.2 percentage points for nonvoters.
Sample View help for Sample
Probability-based Registered Voter Sample: in each of the 25 states in which VoteCast includes a probability-based sample, NORC obtained a sample of registered voters from Catalist LLC's registered voter database. This database includes demographic information, as well as addresses and phone numbers for registered voters, allowing potential respondents to be contacted via mail and telephone. The sample was stratified by state, partisanship, age and race. In addition, NORC attempted to match sampled records to a registered voter database maintained by L2, which provided additional phone numbers and demographic information. After the matching, NORC had phone numbers for 86 percent of sampled records, including cell phone numbers for 60 percent of records with a phone number. Prior to dialing, all probability sample records are mailed a postcard inviting them to complete the survey either online using a unique PIN or via telephone by calling a toll-free number. Postcards are addressed by name to the sampled registered voter if that individual is under age 35; postcards are addressed to "registered voter" in all other cases. Telephone interviews are conducted with the adult that answers the phone. Both online and telephone respondents provided confirmation of registered voter status in the state.
Nonprobability Sample: Nonprobability participants were provided via the Harris Panel, including members of its third-party panels. Digital fingerprint software and panel-level ID validation is used to prevent respondents from completing the VoteCast survey multiple times. Nonprobability respondents provided confirmation of registered voter status in the state.
AmeriSpeak Sample: during the initial recruitment phase of the AmeriSpeak panel, randomly selected U.S. households were sampled with a known, non-zero probability of selection from the NORC National Sample Frame and then contacted by U.S. mail, email, telephone and field interviewers (face-to-face). The panel provides sample coverage of approximately 97 percent of the U.S. household population. Those excluded from the sample include people with P.O. Box-only addresses, some addresses not listed in the USPS Delivery Sequence File and some newly constructed dwellings. AmeriSpeak panelists provided confirmation of registered voter status in the state.
Universe View help for Universe
Registered voters in the 50 U.S. states.
Unit(s) of Observation View help for Unit(s) of Observation
Data Source View help for Data Source
Registered voter self-report
Data Type(s) View help for Data Type(s)
Mode of Data Collection View help for Mode of Data Collection
Response Rates View help for Response Rates
4.2 percent for the probability sample drawn from the state voter files.
Presence of Common Scales View help for Presence of Common Scales
None
HideWeight View help for Weight
VoteCast employs a four-step weighting approach that combines the probability sample with the nonprobability sample, and refines estimates at a subregional level within each state. The 50 state surveys and the AmeriSpeak survey are weighted separately and then combined into a survey representative of voters in all 50 states. For detailed weighting information, see the PI Codebook.
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These data are freely available to data users at ICPSR member institutions. The curation and dissemination of this study are provided by the institutional members of ICPSR. How do I access ICPSR data if I am not at a member institution?