How CNN conducted its deep dive into independent US adults

By Jennifer Agiesta, CNN

(CNN) — The CNN poll conducted by SSRS was designed to offer a deep-dive look at the different types of independents that make up this critical group in American politics.

The survey was conducted both online and by telephone from August 21 through September 1. The 2,077 adults who took the poll were selected from two sample sources – the SSRS Opinion Panel and a list of registered voters, including some who had previously taken a CNN survey conducted in April. The survey included 1,006 political independents, defined as people who said they were independents or did not identify with either major political party. The sample was designed to include a larger than usual number of political independents in order to get a more reliable picture of their views. It was then weighted to partisan benchmarks obtained from CNN’s May 2025 national survey so that each party represents its proper share within the full adult results. The full sample was also weighted to demographic and other benchmarks to ensure that it is representative of the adult population.

Independents’ answers to the survey questions were combined to create five different scales assessing the depth of respondents’ connections to the Democratic and Republican parties, their level of political engagement, their confidence in the political system, the extent to which they feel represented by the political system and their degree of openness to both Democrats and Republicans. Those scales were used as part of a statistical technique called K-means cluster analysis – which groups together respondents with similar answers across all five scales into separate groups – to create the five resulting subgroups of independents.

The project took inspiration from a 2007 Washington Post/KFF/Harvard School of Public Health project which also segmented political independents using similar techniques. Several questions from the 2007 survey were repeated in the new poll. Three of the resulting groups in the new project are similar to those found in 2007. The other two are quite different, likely reflecting the significant changes in the American political climate over that time.

Results for the full sample have a margin of sampling error of plus or minus 2.7 percentage points. Among the sample of 1,006 independents, the error margin is +/-4.2 points. The margin of sampling error for results among the five subgroups of independents ranges from +/-7.9 percentage points to +/-10.7 points.

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