Correct voting in elections has been extensively analysed in the recent past. However, thus far, correct voting in direct legislation has hardly been investigated. This is all the more surprising since direct legislation is a more demanding form of democracy and, thus, to vote one's true preferences in direct legislation represents a greater challenge than picking the “right” party or the “right” candidate at elections. Moreover, the few researches on the correctness of individual referendum votes used a measurement method that we think has some methodological shortfalls. Instead, we want to propose another better-suited method of measuring correct voting in direct legislation settings. This method makes use of voters' stances on the issue at stake. Besides, we will scrutinize the share of correct voting as well as its determinants on the Swiss popular vote of November 2009, which included three rather different propositions. The study shows that a majority of Swiss voters are indeed able to vote their true preferences. The ability to vote correctly depends primarily on the individual voter's project-specific knowledge, but also, under certain circumstances, on the use of heuristics.