There are three major credit bureaus: Equifax, Transunion, and Experian. These bureaus gather information and use convoluted and complex algorithms to calculate a person's FICO score. All three credit bureaus use a different system and they all produce a different score. They only monitor a person's credit accounts, how much is owed, how well the balances are paid, and more. If a person pays cash for most things, has a good paying job, and is a very responsible person, that does not figure into your score. They only use a person's credit accounts to compute a score. My book gives a person the knowledge of how the system works, and it is up to the person how they will use this knowledge.