Healer 'damage parses'

Hi.

I was wondering how the logs determin if the damage on a boss qualify as ‘healer damage’. For instance, if a healing priest do not heal, but only spam smite he will not qualify for a healing parse thus competing with the other dps in rankings.

My question is, do you need to do more healing than damage to qualify for a healing parse and a ‘damage’ healer parse, or do you just need to do 1 healing spell? I’ve looked through the forum but can’t find an answer. Checking logs it seems random to me.

I appreciate WCL and the work you do. Thanks!