Method for AP-Yahoo Poll on Obama gains (AP via Yahoo News)

The AP-Yahoo News Poll is a unique study that will track the moods and opinions of a group of people throughout the presidential election campaign. The fourth wave of this study included re-interviews of 1,844 people between Apr. 2-14 who originally were interviewed in November or early December. The extensive national survey was conducted by Knowledge Networks of Menlo Park, Calif., under the ...