Here is an update on our work on surveybias.
How can we usefully summarise the accuracy of an election opinion poll compared to the real result of an election? In this blog, we describe a score we have devised to allow people to see how different polls compare in their reflection of the final election result, no matter how many parties or candidates are standing. This index, B, can be compared across time, polling company and even election to provide a simple demonstration of how the polls depicted public opinion in the run-up to polling-day
Source: How to measure opinion poll inaccuracy in elections – The Plot (now, sadly, defunct)