Realosophy has a good write-up about what seems to be the big issue with TREB's reporting...
Can We Trust Real Estate Statistics Published by the Real Estate Industry
James, we inside the industry are aware that these monthly sales numbers are later adjusted for deals which fell through. The good news is that Market Watch is usually used by the agents for historical data, and the main number we depend on is not the number of sales, but the ASP (Average Selling Price). That number doesn't change all that much by the adjustment. I would say that the number of sales which fall through on a monthly basis are offset by the number of pocket listing deals which are done (discussed previously in this thread).
I rarely depend on the Market Watch data because you can't compare apples to oranges. Just because the ASP in January 2013 was 10% higher than January 2012 does NOT mean that each and every property increased in value by 10%. The number of sales also doesn't tell us agents all that much. We already feel the pulse of the market by being out there, and we can feel the change week to week, depending on so many factors, which can include inclement weather, whatever Flaherty has had published that week, news about the US market improving or declining, etc etc etc.
On another note, we need to be careful about copying and pasting whole articles on UT which are covered by copyright law. We can link to the article, and we can quote portions which are covered by editorial use, but we should be respectful of copyright. A small but important consideration.