Fortunately, figuring out the value of a company’s stock is not simple or easy. If it were, everyone would do it! Teams of experienced Brandes investment professionals work full time to estimate stock values. Not only does this require extensive research and analysis, but an appreciation that values are not exact and can change over time, as circumstances change. Nevertheless, having a reasoned estimate of a stock’s value is an essential first step to figuring out how much is “a lot less” to pay. 

Source: WealthManagement.com, “Anyone—Even the Little Guy—Can Beat the Market,” by Joel Greenblatt, June 8, 2011