Fair Isaac, which developed FICO scores, used a comparison between two people to explain how mortgage delinquencies affect credit scores.

Fair Isaac derived these numbers from a theoretical calculation based on hypothetical borrowers – one with an initial score of 680 and one with an initial score of 780. FICO scores range from 300 to 850.

The hypothetical person behind the 680 score had six credit accounts, while the person with the 780 score had 10. The consumer with the 780 score had no missed payments other than the mortgage; the 680 example had two late payments before they failed to pay the mortgage.

After a mortgage payment problem, the two scores would look like this:

• After a 30-day delinquency, the 680 score drops to somewhere between 620 and 640; the 780 score declines to 670 to 690.
• After a 90-day delinquency, the 680 score falls somewhere between 595 and 610; the 780 score goes to 645 to 665.
• After a foreclosure, short sale or deed-in-lieu, the 680 goes somewhere between 575 and 595 and 780 drops to 620 to 640.
• After a bankruptcy, the 680 drops somewhere between 530 and 550; the 780 declines to 540 to 560.