---
title: "About the Surveys"
description: "Results for the national survey are based on telephone interviews conducted under the direction of Schulman, Ronca, & Bucuvalas, Inc. among a nationwide sample of 1,399 adults, 18 years of age or older, from November 20-26, 2007. For results based on the total sample, one can say with 95% confidence that the error attributable to […]"
date: "2007-12-04"
authors:
  - name: "Seth Rubenstein"
url: "https://www.pewresearch.org/politics/2007/12/04/about-the-surveys-66/"
categories:
  - "Election 2008"
  - "Politics & Policy"
  - "U.S. Elections & Voters"
---

# About the Surveys

Results for the national survey are based on telephone interviews conducted under the direction of Schulman, Ronca, & Bucuvalas, Inc. among a nationwide sample of 1,399 adults, 18 years of age or older, from November 20-26, 2007. For results based on the total sample, one can say with 95% confidence that the error attributable to sampling is plus or minus 3 percentage points. For results based on likely Republican primary voters (N=448), the error attributable to sampling is plus or minus 5.5 percentage points.

Results for the state surveys are based on telephone interviews with a sample of 5,462 adults living in Iowa, New Hampshire, and South Carolina, conducted by Princeton Data Source, LLC under the direction of Princeton Survey Research International, from November 7-25, 2007.

The Iowa survey interviewed a total of 2,111 registered voters, including 264 who say they will definitely or probably attend a Republican caucus. The margin of error for those likely to attend a Republican caucus is +-7%.

The New Hampshire survey interviewed a total of 1,300 registered voters, including 446 who plan to vote in the Republican primary. The margin of error for those who plan to vote in the Republican primary is +-5.5%.

The South Carolina survey interviewed a total of 1,200 registered voters, including 468 who plan to vote in the Republican primary. The margin of error for those who plan to vote in the Republican primary is +-5.5%.

In addition to sampling error, one should bear in mind that question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of opinion polls.