The Government of Alberta requires the City to assess all property within Medicine Hat every year using a mass appraisal approach. The assessed value of your property noted in your assessment notice is your property's estimated market value (the amount it would most likely have sold for based on the mass appraisal in the open market on July 1 of the previous year.)
To establish an assessed value of your property, the City uses information on real estate sales that occurred up to and including last July 1 and information on any physical changes recorded up to last December 31.
A range of sale prices results when similar properties are sold during the same time frame. Assessed values reflect the sales in the middle of this range of prices. That is one of the reasons why your assessed value may be higher or lower than the price you purchased your home for.