Q: How are assessments established?

A:  The assessment act requires that your property's assessed value be based on what it would likely have sold for on a specific date. For the 2011 taxation year, that date is January 1, 2008. 
To establish your property's assessed value, MPAC analyzes property sales in your area. These sales provide a basis for the assessed values of similar properties. MPAC continually collects information about properties to ensure that those with similar features (age, size, location, construction, etc.) have similar assessed values. 

This method, called "current value assessment", is used by assessment jurisdictions in most provinces and other countries.