Share your insights or perspective on the financial matter presented in the input.

Why is it important to research a stock before buying it?
The following is only an overview and does not contain all of the in-depth reasons why you should look more deeply. When you look at a stock's financials in depth you are looking for warning signs. These may warn of many things but one important thing to look for is ratio  and growth rate manipulation. Using several different accounting methods it is possible to make a final report reflect a PE ratio (or any other ratio) that is inconsistent with the realities of the company's position. Earnings manipulation (in the way that Enron in particular manipulated them) is more widespread than you might think as "earnings smoothing" is a common way of keeping earnings in line (or smooth) in a recession or a boom. The reason that PE ratio looks so good could well be because professional investors have avoided the stock as there appear to be "interesting" (but legal) accounting decisions that are of concern. Another issue that you don't consider is growth. earnings may look good in the current reporting period but may have been stagnant or falling when considered over multiple periods. The low price may indicate falling revenues, earnings and market share that you would not be aware of when taking only your criteria into account. Understanding a firm will also give you an insight into how future news might affect the company. If the company has a lot of debt and market interest rates rise or fall how will that effect their debt, if another company brings out a competing product next week how will it effect the company? How will it effect their bottom line? How much do they rely on a single product line? How likely is it that their flagship product will become obsolete? How would that effect the company? Looking deeply into a company's financial statements will allow you to see any issues in their accounting practices and give you a feel for how they are preforming over time, it will also let you look into their cost of capital and investment decisions. Looking deeply into their products, company structure and how news will effect them will give you an understanding of potential issues that could threaten your investment before they occur. When looking for value you shouldn't just look at part of the value of the company; you wouldn't just look at sales of a single T-shirt range at Wallmart when deciding whether to invest in them. It is exactly the same argument for why you should look at the whole of the company's state when choosing to invest rather than a few small metrics.