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Polling Methodology

The Daily Kos/SEIU State of the Nation Poll is conducted each week (excluding those with major holidays) by Public Policy Polling ("PPP"). Respondents are chosen randomly from a nationwide voter file provided by Aristotle, Inc. Calls are typically made between Thursday and Sunday of each week, and at least five attempts are made to reach each potential respondent over the course of those four days. Respondents are interviewed through an automated telephone survey with the exception of those in Indiana and North Dakota, who are contacted via live telephone interviews because of restrictions on automated telephone calls in those states.

Typically, poll respondents represent a greater proportion of whites, older people, and women than found in the American public as a whole. Because of this, PPP weights its polls for race, age, and gender to ensure its surveys properly represent the population. (Note: PPP does not weight for party identification.) Based on a combination of census numbers, voter participation in past elections, and poll response, PPP develops target ranges for the share of poll respondents that should fall into each of these categories.

After contacting a sufficient number of respondents, PPP uses a random deletion process to achieve an appropriate gender and race balance, which generally involves removing excess cases of white and female voters. PPP then uses a statistical formula to adjust for age imbalances, which creates the final results. Even though the final results are weighted, the number of respondents by gender, race, and age is not necessarily identical every week.

Using a statistical formula to weight the results can result in a round number of respondents in each demographic category because the Daily Kos/SEIU State of the Nation Poll generally has a base of 1,000 respondents. However, an examination of the raw data (which is also provided each week) demonstrates that this pattern does not exist at the individual respondent level, but rather is merely a by-product of weighting.

In addition to the raw data used to generate the final results, Daily Kos and SEIU also make available the raw data discarded via the random deletion process described above. The discarded data is not used in calculating final poll results and is provided only for the purposes of transparency.

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