I am not arguing with the principle here, I’m trying to point out that precision of the estimates are very important. For example, the difference betwen a price-to-rent ratio of 12 versus 8 translates to a huge difference in price (33% is large, no?).
As for your comment about skewed numbers…
There are 137 different neighborhoods in San Diego. There are great differences in attractiveness, size of house, size of lot, etc. The San Diego aggregate numbers get skewed by the big homes/big lots, the oceanside homes in Sunset Cliffs, the homes walking distance to the beaches, etc.