The reality is that we don't.
Why then do we ask you for it when you first come into our office?
The reason we ask for it is so we can have it in our files. We keep it in our files until the lawsuit has been started and the attorneys for the people you have sued have requested certain documents from us. Part of the information that is requested from us in a process known as “discovery,” is to provide the defense with your Social Security number.
Why would they want this information?
Simple. They want to do their own background investigation and they want to learn as much as possible about you during the course of the litigation.
One of the ways to do this is with your Social Security number.
By law, we are required to provide this information to the defense attorneys. It allows them the ability to do background checks on you as well as investigate your past and current issues.
If there are skeletons in your closet, you would do well to tell your attorney about them on the first visit so that he can deal with it as the case progresses through the discovery process.
Based upon the investigation performed by the defense attorney, you will then be asked many questions at your deposition, which is a question and answer session, given under oath. It is pretrial testimony. If the defense has damaging information, they will ask you about it at your deposition, it would be to your benefit to simply admit what ever was in your history and to move on.
If you try and hide something damaging, the defense will later show that you lied under oath. It is much better to admit something that has been damaging in the past and to simply move on.