Since January 2014, Fabio Wasserfallen and I have been running surveys in Switzerland before each ballot measure for a large newspaper. We usually conduct three waves, about fifty, thirty, and ten days before the actual vote takes place. Unlike traditional polls we rely on online surveys and employ extensive statistical modeling to produce good estimates of the likely outcomes of the referendums (see below).
The last survey is always reported 10 days before the final vote. One way to assess our estimates is to compare the estimated support ten days before the vote with actual outcome. We compare our results (20min Yes %) with our major competitor's estimates (GfS Yes %). Past performance is good and in over 60% of cases we are closer to the final outcome than the traditional telephone survey. We also have a prediction model (not published) which is based on our three waves and performs very well.
A short report with a more detailed description of what we do (and how this contrasts with traditional polling approaches) is available here - unfortunately, it is only available in German. Do not hesitate to get in touch with me if you have any questions about this polling work.
POLLING & SURVEYS