OLC statistics

I flew with several much more advanced pilots on Saturday, 4 hours in
100% ridge lift, very turbulent, very rough terrain (North Cascades WA
State), very cool. Afterwords it was pointed out to me that my Rate Of
Climb statistic was 1/2 of everyone else, although I was keeping up
altitude wise. Is there an explanation somewhere of what is being
measured, and is there a way of using it as a training tool?

Thanks all,

Brian