Relative values are added to the previous value. For example, if i tick the 'relative' box, then each time i collect a coin, 10 points will be added to the previous player score:
So if my previous score was 10, my new score will be 20.
Absolute values (not relative) are not added to the previous value. If i use the same example but untick 'relative', then no matter what my previous score is, my new score will always be 10:
So if my previous score was 10, my new score will still be 10 (if i have unticked 'relative').