Okay, let's go through a few additional specifics here. When you're doing heuristic evaluation, you generally want to go through or explore each interface at least twice. So in the first pass, you want to explore the interface. Just generally, just see what's there, get an idea of the scope of the system. And then, in your second pass, you're grinding through the details, you're listing out those problems, in each part of the interface. So in the first pass, you're typically kind of mapping where things are, in the second pass you're doing more or less the real work. When you're doing a heuristic evaluation in general, you're not performing a specific task, you're exploring. But there are some exceptions to that rule. Many times user interface design experts are asked to evaluate a system in a domain they don't understand. Say for instance if I were asked to evaluate a system Professor Yuroshi is here watching me record this today, a system on some of her research topics like a system for children, or a system that maybe is for caretakers of the elderly. Well I don't know too much about that, I'm not a domain expert. So what Professor Yuroshi might do is say hey, here's a scenario. Can you do a heuristic evaluation according to this scenario.