A: Let's say you bring a lawsuit against the drivers of two different cars for causing your car crash.
At the end of the case, the jury will be required to determine by what percentage each driver was responsible for causing your accident.
Negligence in its basic form means carelessness. 'Comparative' means that you're comparing the responsibility of each of the people that you have sued. The specific facts of your case will allow the jury to make a determination about each of the wrongdoers' percentage of fault.
Interestingly, the jury will also need to evaluate whether you, the injured victim, were partially at fault for causing or contributing to your own injuries.