A summary of ABC News polling standards and methodology follows.
Langer Research Associates, primary polling provider to ABC News, advises the news division on standards for disclosure, validity, reliability and unbiased content in survey research, and evaluates data when requested to establish whether it meets these standards.
On disclosure, in addition to the identities of the research sponsor and field work provider, we require a detailed statement of methodology, the full questionnaire and complete marginal data. If any of these are lacking, we recommend against reporting the results. Proprietary research is not exempted.
Methodologically, in all or nearly all cases we require a probability sample, with high levels of coverage of a credible sampling frame. Self-selected or so-called “convenience” samples, including internet, e-mail, “blast fax,” call-in, street intercept, and non-probability mail-in samples do not meet our standards for validity and reliability, and we recommend against reporting them.
We do accept some probability-sample surveys that do not meet our own methodological standards – in terms of within-household respondent selection, for example – but may recommend cautious use of such data, with qualifying language. We recommend against reporting others, such as pre-recorded autodialed surveys, even when a random-digit dialed telephone sample is employed.
In terms of content, we examine methodological statements for misleading or false claims, questionnaires for leading or biasing wording or ordering, and analyses and news releases for inaccurate or selective conclusions.
In addition to recommending against reporting surveys that do not meet these standards, we promote and strongly encourage the reporting of good-quality polls that break new ground in opinion research.
Field work for most of ABC’s U.S. polling is carried out by Abt SRBI of New York, N.Y., using a dual-frame sample design covering both landline telephone and cell phone-only respondents, with samples produced by Survey Sampling Inc. of Shelton, Conn. We tested cell-only sampling in August 2008, made it a regular part of our sample design in October 2008 and reported on our approach in detail at the annual meeting of the American Association for Public Opinion Research in May 2010; see that paper here.
In the landline component of these surveys, a sample of landline households in the continental United States is selected by SSI via random digit dialing procedures, in which all landline telephone numbers, listed and unlisted, have an equal probability of selection.
SSI starts with a database of all listed telephone numbers, updated on a four- to six-week rolling basis, 25 percent of listings at a time. This database of directory-listed numbers is then used to determine all active blocks – contiguous groups of 100 phone numbers for which more than one residential number is listed. All possible numbers in active blocks are added to the random digit database.