Question Weighting in Knowledge-Based Authentication (KBA): Part 2

— by, Andrew Gulledge

One of the quickest and easiest ways to reduce fraud in your portfolio is to incorporate question weighting into your out of wallet question strategy. To continue the use of knowledge based authentication without question weighting is to assign a point value of 100 points to each question. This is somewhat arbitrary (and a bit sloppy) when we know that certain questions consistently perform better than others.

So if a fraudster gets 3 easier questions right, and 1 harder question wrong they will have an easier time passing your authentication process without question weighting. If, on the other hand, you adopt question weighting as part of your overall risk based authentication approach, that same fraudster would score much worse on the same KBA session. The 1 question that they got wrong would have cost them a lot of points, and the 3 easier questions they got right wouldn’t have given them as many points. Question weighting based on known fraud trends is more punitive for the fraudsters.

Let’s say the easier questions were worth 50 points each, and the harder question was worth 150 points. Without question weighting, the fraudster would have scored 75% (300 out of 400 points). With question weighting, the fraudster would have scored 50% (150 out of 300 points correct). Your decisioning strategy might well have failed him with a score of 50, but passed him with a score of 75. Question weighting will often kick the fraudsters into the fail regions of your decisioning strategy, which is exactly what risk based authentication is all about.

Consult with your fraud account management representative to see if you are making the most out of your KBA experience with the intelligent use of question weighting. It is a no-brainer way to improve your overall fraud prevention, even if you keep your overall pass rate the same.

Question weighting is an easy way to squeeze more value of your knowledge based authentication tool.