538.com pollster ratings: Who’s got the mojo, who does not

Nate Silver of fivethirtyeight.com

Nate Silver, the baseball/sabermetrics guru who brought a new level of sophistication to the analysis of political numbers when he launched fivethirtyeight.com in March 2008, posted a revised set of numbers on the most accurate political pollsters in the land last month.

Of local interest:

• SurveyUSA, which does polling for KSTP-TV, came in third nationally among organizations with more than 10 relevant polls to their credit;
• Rasmussen Reports, which handles Fox9’s surveys, came in 15th.
• And the Star Tribune came in at 48th.

Silver explains his methodology in detail, but here’s the most critical piece: “These ratings pertain to just one particular type of poll: those for which the field work was conducted within the 21 days preceding a public election, which surveyed people about their voting intention in that election, and which was released into the public domain in advance of the election.”

Here’s the rankings chart for orgs with more than 10 such polls in their background; you can get more details and more extensive rankings notes here.