This is a debate that has been ongoing for well over 20 years now. That is what is the accuracy of an AVM if the data is collected and crunched by a computer versus having a traditional appraisal completed. The main complaint from the appraisal community has been that the computers have never actually seen the property nor the neighborhood and therefore have no relevant market information to provide credible results. This still holds true today even in the world of Zestimates and Redfin estimated market values. These online home sellers use data points in the market and then plug that information into a computer that spits out a number based on that data. However in most cases this does not factor in things like adverse locations, interior condition and amenities the property might have. As a result a misleading “value” is produced which can sometimes lead people to list a home with inaccurate information.
Here is a link to a great article that might shed some more light on the AVM issues.