A stock screener is a tool that traders and investors can utilize to filter stocks based on user-defined metrics, according to Investopedia. It allows investors to analyze large numbers of stocks in a relatively short period of time.
A stock screener should be the first tool one masters when beginning to learn how to do stock research, advises About.com. Common metrics that a user might filter by include price, P/E ratio, market capitalization, dividend yield and average volume. Many stock screeners are free, and one of the easiest and simplest to use is MSNMoney.com's stock screener, which is available in both basic and deluxe editions.