California's venerable Field Poll is the nation's most reliable political poll in terms of reflecting outcomes, according to FiveThirtyEight, a Chicago-based website that specializes in political data.
The website -- named for the number of votes in the presidential electoral college -- is the handiwork of Nate Silver, who runs a sports media company called Baseball Prospectus and says, "baseball and politics are data-driven industries. But a lot of the time, that data might be used badly. In baseball, that may mean looking at a statistic like batting average when things like on-base percentage and slugging percentage are far more correlated with winning ballgames. In politics, that might mean cherry-picking a certain polling result or weaving together a narrative that isn't supported by the demographic evidence."
To rate the reliability of political polls, Silver collected 4,700 polls in races for president, U.S. Senate, Congress and governorships since 1998, plus the outcomes of the contests, and devised a reliability index that he applied both to polls with 10 or more surveys and those with any number.
The Field Poll, founded by Mervin Field more than 60 years ago and based in San Francisco, came out on top of both listings, bettering even the Gallup Poll and those conducted by national news organizations. The Public Policy Institute of California's poll ranked 31st in the latter group but the state's third major poll, conducted by the Los Angeles Times, ranked near the bottom.
The Field Poll appears in the Sacramento Bee and other newspapers. The full FiveThirtyEight rankings are available here.