Originally posted by @Sam Stout:
Isn't Zillow in a lawsuit right now because their "zestimates" were so far off it was giving people false impressions about the value of their homes? No disrespect to you @Account Closed, I completely understand your point and it's a good one, but I try not to trust Zillow.
http://www.marketwatch.com/story/do-zillow-zestima...
Lawsuits often come with the territory... its almost like a cost of doing business. You rely on Zillow's Zestimate at your own risk... I personally would have a realtor pull comps on a particular property but there are times you may not have instant access to a realtor or mls based data and have to be able to utilize Zillow or any of the other sites to get estimates.
Even realtors try to manipulate comps and so I often will have to advise the realtor to make some adjustments to a comp if the properties utilized in the analysis, area or some other characteristic do not align with the subject.
If you have the capability to capture the amount of real estate transactions such as Zillow does; not just in a particular city, state but at a country level, including granular details of those transactions, you have a right to make logical and defensible opinions about market place events and behavior. Its not just Zillow, there are other companies in the space -- Zillow just happens to have the most market share currently.
When you are looking at historical market data, transactions that already occurred, these are a matter of fact. MLS based comps are often based off of the very same transactions.
When you move from looking at historical data and attempt to forecast the future... there isn't an algorithm that can do so without any error, as there are an array of complex factors and economic events that some piece of software cannot be expected to see. If humans, including 'experts' in any field, can't precisely with 100% certainty forecast any particular event -- you can't expect zillow or the zestimate tool to.
Many websites attempt to estimate property value and there are variances between most or all of them. You do not rely on any particular one of them nor do you accept a realtors comp at face value -- you could, but that would be at your own risk.