just because a participant fails to perform a task immediately doesn’t mean that she won’t discover the right answer with a little exploration. Watching where she explores first can be incredibly helpful in understanding a participant’s mental model of the application. So let her fail for a while, and then give her a small hint to help her toward her goal. If she still doesn’t get it, you can keep giving stronger hints until she’s completed the task, or you can just move on to the next thing while making a note that you’ve found something you need to fix.
More important to understand how users think about the product
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