Republicans and Democrats have inaccuracies about what each other believes, and the more extreme they are themselves, the more inaccurate they are about the other. Instapundit linked to an article about it in The Guardian. The info is based on data generated from the site More In Common. I did moderately well - in fact my biggest outliers were issues where Democrats were more extreme than I expected. As I was coming in from links talking about how badly both sides did, however, my result should be taken with a heaping of salt. I likely modified my answers in the direction of painting Democrats as less extreme than I thought, in response to the articles.
The most dramatic item reported by both Instapundit and The Guardian was technically accurate, but I thought misleading. Democrtats got less and less accurate the more education they had, so that those without a high school diploma were three times more accurate about Republicans than those with graduate degrees. This was true, but was against a background of Republicans doing generally worse, only nudging ahead at the graduate level. The less-educated Democrats were by far the most accurate of all respondents about what the other side thinks.