Over fifty years ago, Bill Fair and Earl Isaac (a mathematician renowned as the first person to crash a computer) started the Fair Isaac Corporation as a consulting form for the financial industry. They’re still regarded among leading authorities of their field, but most every American – from teenagers looking for their first car loan to grandparents hoping to re-finance – are at least dimly aware of the company because of their not-so-simple 1958 invention: the FICO model for credit scoring.

Essentially, the FICO system uses a method of statistical analysis to evaluate potential applicants’ credit worthiness independent of their greater financial holdings or external criteria. The score was intended to not judge borrowers by age, income, race, region, or marital status but instead purely look at their past scenarios of debt capacity and repayment through a set of blind mathematical processes. Therefore it is important for those in debt to seek debt relief.

Each of the big three credit bureaus – Equifax, TransUnion, and Experian – calculate their own FICO scores with available data (which is why all three credit scores are pulled for large purchases, such as mortgages, with the highest and lowest scores pulled out).to determine a borrower’s risk quotient by assigning numerical values to each element of their credit history and employing algorithms which create an overall score between 375 and 850. Generally, scores above 700 are considered ’A’ credit and those below 640 are considered suspect, but, of course, every lender and every situation demands their own specific expectations.

The exact formulas of the FICO scoring model are closely guarded, and, without knowing what values are placed upon what sort of credit transactions, it’s impossible for individual borrowers to attempt their own calculations. Still, we do know the primary aspects that affect the FICO score. They can be separated into two categories:

Credit History

There are two sorts of credit accounts, installment (mortgages, for example, which are usually secured and have set end dates) and revolving (e.g. credit cards). Financial consultants urge borrowers to maintain both types of accounts. It’s advantageous to have credit lines that have lasted for an extended period, but those opened within the last two years are more significantly valued. Also, make sure to not have any one revolving account too close the spending limit – that negatively impacts the FICO score.

Payment History

Delinquent payments, obviously, can lower credit ratings. 30, 60 and 90-day-lates are progressively worse, and debts sent to collection agencies or charged off by the creditor will dramatically affect the overall score. The credit bureaus are also kept aware of any liens or judgments (or, especially, bankruptcies) filed against the borrower.

There are other considerations, of course – repeated checks of FICO scores can themselves lower the outcome; lenders presuming frequent inquiries to be signs of desperation – but, once again, the specific computations remain a mystery. Regardless, maintaining a variety of accounts with low balances and paying bills on time should raise every consumer’s score – even if nobody’s quite sure why.