My main priority when assessing debaters is to see whether a speaker is able to fully understand their opponents points and directly compare it to their own contentions. I believe one of the greatest skills students can pick up from debate is to be able to listen to your opponents and effectively address their arguments, not just being able to defend your own. If a debater can compare and clash their arguments with their opponents and use logic + evidence to justify why, in the context of that debate round, their contentions are better, then I believe they have a strong chance of winning.