This morning I answered a question on a popular real estate site about how a Livonia MI home could sell so cheaply ($90K) in an area of expensive homes without being listed for sale.
Turns out the home in question was in a new subdivision of about 70 homes so it was purchased through the builder. Upon further investigation, I discovered that after the transaction closed, only the sale of the parcel of land was recorded as the real estate 'sale' on public records. Also recorded was mortgage for over $300K. That doesn't account for how much the Buyer might have paid as a down payment.
It's become so easy to do home value research online through sites like Zillow and Trulia. However, until each municipality standardizes how new construction transactions are to be recorded, data will continue to be skewed and deceptive.
Your best resource for local home values is still a local professional real estate agent who can fill in the full picture for you.