A credit score is often described as a measure of how responsible a borrower is, but that is not quite what it does. It is a prediction, built from past behaviour, of how likely a lender is to be repaid. The distinction matters because the two can come apart. Someone who has never borrowed at all may be entirely reliable and still score poorly, simply because there is no record to predict from. Someone else who carries debt and pays the minimum on time every month may score well while sliding slowly into trouble. The score answers the lender's question, not the borrower's.