You can basically think of ChexSystems report as the banking version of your FICO score. Just like the credit history agencies that track your credit history, ChexSystem monitors your banking behavior and makes this information available to financial institutions.
Just like credit FICO scores, ChexSystems gives you a rating between 100 and 899. The higher your rating, the better you are rated for banking. However, unlike the Credit Bureaus which keep records of both positive AND negative credit history, ChexSystems (and the reports banks look at) only contain NEGATIVE information.
This basically means that your ‘good’ behavior is not at all counted. Once you have your name in ChexSystems, you are treated negatively by banking institutions. If two people have committed some banking mistakes, but one of those persons has also had some good banking relationships, both of those people may be declined from opening a new banking account.