• An unrealistically simplified scenario is banded multiple-choice questions regarding a person's income, outgoings and savings.
• A low score on all three questions would give a low credit rating
• A high score on all would give a high credit rating
• Inbetween would be less clear. 
  Depending on how it was set up, a credit rating for high income band might be better than for high savings.  Similarly, a low income and low outgoings might be better than a high income and high outgoings, but not necessarily better than average income and average outgoings.

In other words, the credit rating is based on all of the answers and this is where weighting comes in.

If savings are only half as important than income then the weighting for savings might be 5 and the weighting for income 10. If the weighting for outgoings (using reverse numbering scheme) is 0.8 time as important as income, the weighting would be 8. Therefore a person in the top savings band would score 4 x 5 = 20 whereas a person in the top income band would score 4 x 10 = 40, a person with low income and outgoings would score 1x10 + 4x5 = 30, low income and high outgoings 1x10 + 1x5 = 15, low income, high outgoings and middle savings 1x10 + 1x5 + 3x8 = 39, and middle income and outgoings 3x10 + 3x5 =45.