The first card sort we tasked beta testers with completing was an "open" sort. In an "open" sort participants are asked to not only group content cards but to label the groups they've created. In the next card sort, we will be inviting our beta testers to complete a "closed" sort. In a "closed" card sort participants are provided pre-defined group labels and then asked to sort the content cards into those groups. The group labels provided aren't necessarily the finalized names that we will be using for navigation, but they are clear and descriptive enough to allow sorting and grouping.
A "closed" card sort is useful in creating a consensus on how content should be grouped. Not all the cards from the previous sort will be included in the "closed" sort. We're removing cards whose grouping is predictably certain and are instead focusing on cards whose placement can be more subjective to users.