On the whole, we say that this is high-quality data. However, we observed a sharp increase in multiple responses between 2006 and 2011, for example. By matching the files, we realized that people who had given two or three answers in a census gave only one in the following census.
We said we had to be cautious in comparing recent data with data from previous censuses because the tool changed in 2011. The language questions are now on the short form, and that may influence the way people respond.
It may seem easy to put a question on the questionnaire, but it must be understood that the position of the question on the questionnaire may result in considerable changes, depending on the communities or the questions.