By now, you likely know that a background check is a great way to look into a person's criminal history or presence on the sex offender registry. But understanding how online background checks work makes it easier to know how to put them to use for you. 1. You can access information that is part of the public record. If a crime occurs and is never reported to the police, there's no way it can show up on a background check. An online background check accesses information that has entered the public record. This may be through court proceedings, documents made available electronically, state or county files, or other government records. If it's not public record, it won't show up on a background check. 2. Background checks have reverse look-up functionality to make searching easier. To get the best information, you need to know a few things about the person you're trying to look up. For example, there might be six John Walkers living in your city, so knowing a middle name or initial is key. Even better is having basic details such as an address or phone number, which can help with reverse look-up functions to access public records. 3. Online background checks give information about licensing. An online background check doesn't simply give a listing of arrests and police records -- it contains much, much more. Perhaps the person is a former pilot with a Federal Aviation Administration license. Or maybe she has a Drug Enforcement Administration license. Getting an individual's licensing information can give you key details about his or her past. 4. Background checks include marriage and divorce records. That sweet-talker from your local watering hole may have convinced you to go on a date, but you've got lingering questions about his relationship history. A background check turns up an individual's marriage and divorce history, giving you key information. 5. Background check information can never be 100% guaranteed to be accurate. Most online background checks provide thorough, reliable information. However, records get mixed up or filed under the incorrect name. If you doubt something that appears on a background check, ask the person involved or search for alternative sources. Keep in mind that background check mistakes are the exception, rather than the rule.