A credit score is widely treated as a judgement on a person's financial responsibility. It is narrower than that: a statistical estimate of one specific future event.
The score predicts one outcome
Scoring models are built to estimate the probability that an account will fall a defined number of payments behind within a set future window.
Everything in the model exists because it improved that prediction on historical data, not because it reflects any moral view of the borrower.
This is why the score can look counterintuitive. A behaviour that feels prudent may not correlate with the outcome the model is built to forecast.
Income and savings are not in the file
Credit files record borrowing and repayment, not earnings or wealth. A person with substantial savings and no credit history has little for a model to score.
Lenders assess affordability separately, using income evidence and expenditure checks supplied during the application. The score and the affordability test answer different questions.
An application can therefore fail on affordability while the score is high, or the reverse, since neither measure substitutes for the other.
The main inputs are behavioural and historical
Payment history carries the greatest weight, because past missed payments are the strongest available predictor of future ones.
How much of an available limit is being used matters too, as does the age of accounts and the recent pattern of applications for new credit.
The precise weightings differ between models and are not published, which is why the same file can produce different numbers from different providers.
There is no single universal score
Several agencies hold separate files, and lenders often run their own internal models over the agency data combined with their own customer records.
A consumer-facing score is an indicative figure from one agency's model. The number a lender actually used may never be disclosed.
Because coverage differs between agencies, an account reported to one and not another produces genuine differences rather than errors.
Rules vary by jurisdiction and change
What may be recorded, how long adverse information stays on file, and what rights a consumer has to correct entries are all set by national regulation.
Those rules differ substantially between countries and are revised over time, so guidance written for one market can be misleading in another.
The one durable point is procedural: files can be inspected and disputed, and errors are corrected through the agency rather than through the lender that reported them.