DOI: 10.3886/icpsr37677.v1
title: AP VoteCast, United States, 2018
title: Version 1

description: 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.
description: 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.
description: Response Rates: 4.2 percent for the probability sample drawn from the state voter files.
description: Presence of Common Scales: None
description: <b>Probability-based Registered Voter Sample: </b>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.<b>Nonprobability Sample: </b>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.<b>AmeriSpeak Sample: </b>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.
description: Datasets: 
DS1: AP Votecast 2018 Data
description: Registered voters in the 50 U.S. states. Smallest Geographic Unit: State
description: computer-assisted telephone interview (CATI); web-based survey<b>VoteCast National Survey: </b>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.<b>VoteCast State Surveys: </b>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.