Algorithms and appraisal accuracies

“Weapons of math destruction” Zestimates, E-Valuations, AVM’s (automated valuation model), and the real scoop about how these mathematical algorithms work, and don’t work. A 13-minute TED Talk about how these algorithms affect every aspect of our lives.

Zillow recently spent over $1 million to improve their Zestimates by 0.5% nationwide. These predictions of potential sale price now have a nationwide margin of error (accuracy) of 4.0%. In San Juan and Skagit Counties this margin of error is much greater. The last published median error rate (from Zillow’s website) is almost 10% for San Juan County and 6% for Skagit County with only a fair confidence rating (one step up from no valuation available assessment data only provided).