“Mass appraisal process – mass appraisal uses the cost approach to value homes and owner occupied buildings and the income approach to value income properties. Each appraiser involved in valuation often values over 10,000 properties per year. In some cases, such as land, it is not unusual for the appraisers to each value over 100,000 properties per year. That is 384 properties per day, based on 52 weeks and no days off. Clearly, mass appraisal is at best an informed guess. The cost approach depends upon knowing the interior condition of each of the properties; the appraisal district does not even have accurate information on the exterior of the properties. You should protest annually since the appraisal district does not have information for your property.”
Taken from http://www.cutmytaxes.com/