Question: I just had a group of 4 adults come to an open house that is not vacant and want to view the home but refused to give me any of their information including name. I said I needed at least a name for security and they refused. Would you still let them view? This is also on a 700k home.

- Megan Andersen-Hall, Top contributor

Despite all the data points crunched and algorithms used, the three biggies in the world of home valuation — Zillow, Redfin, and mortgage giant Chase — demonstrate so much disparity that you might think you were comparing a suburban McMansion to its humble tool shed out back. These sites typically use a combination of public and user-submitted data for its formula. However, there are plenty of discrepancies when using all three platforms. As a result, the most vital part of selling your home — its value — is ultimately up in the air. Watch Now!