38 polling firms have polled one or more of the 36 Presidential Primaries and Caucuses to date in 2008. Here’s how the pollsters stack-up, ranked from smallest average error to largest average error (where smaller error is better, and zero is perfect).

Complete supporting detail, and caveats, on the jump …

Not all 38 pollsters polled on the same contests or on the same number of contests. Some contests may have been harder to poll than others.

All information drawn from http://www.realclearpolitics.com/ , from http://www.pollster.com/ and, if disagreement on those two sites, from individual polling firm’s website. No polls or polling firms ere intentionally omitted.

Double-click on the following detailed table if you need to enlarge it to read it.

For a complete discussion of the different ways that election poll accuracy can be measured, including a summary of all 8 known measures, see this paper presented at the 2006 conference of the American Association for Public Opinion Research.

Super Tuesday election returns accurate as of 10 am ET on 02/06/08. In a couple of states, 100% of precincts had not yet reported.

Any errors in this table, or omissions from this table, should be reported to editor@surveyusa.com.

Update: PPP data corrected 020608 5:35 pm ET.