As a former appraiser, Market Value is mostly determined by guaging what a similar property in the area has sold for recently, i.e., comps. But what most people don’t get is that if some dumb sucker paid too much for the house down the street similar to yours, which is really at market value? People have all kinds of reasons why they will pay more for one property and not another, school district, back yard, pool, tile color – some people can see past cosmetic differences and find diamonds in the rough, some have to have their house perfect for them, they do not want to do any cosmetic fixes to perfect the house. I don’t think personally you can determine market value so closely that you can say accurately that the house is “$20,000 below market value”, but rather “$20,000 below recent comps.”