This figure presents the house bias and measurement error adjusted estimates of vote intention over time.
It is based on all published polls to date. The method used to obtain these estimates is available here.
Estimates of party support leading into previous elections can be obtained by clicking on >>
The Polling Observatory provides an analysis and discussion of the vote intention polls and their media coverage.
It also acts to disseminate the latest research on polling accuracy and poll effects on voters. For a list of past blog entries, please click here
Here are the root-mean-squared-errors for the most active pollsters and the Polling Observatory.
*for Nanos I used the final two-day result, which is what I used in my estimates.