What is time trending and why is it necessary?
Residential properties, by law, must be valued solely by the market approach, using comparable verified sales from the study period ending the June 30th prior to January of the reappraisal year. The Assessor may go back in time in six month increments up to five years for their study period data. In Gunnison County, we use a 24 month minimum study period to eliminate seasonal differences that may affect the market in an 18 month period. In reappraisals with low sales volume, 48-60 minths sales may be necessary to comply with audit requirements. These same statutes require the adjustment of sales prices within this study period to the end of the data period. Sales of residential homes taking place during the sales study period are analyzed to establish the residential time trend adjustments. Since the law requires that sales prices be adjusted for time to the end of the study period on the June 30 appraisal date, it’s as if all homes that sold during the study period were sold on the Ju
