What are the differences between groups and sets?

A group merges dimension members into higher-level categories — twenty subcategories into five buckets, or several spellings of the same city into one. The result is a new dimension whose members are your buckets. Membership is by name, so a new member that appears later lands in Other until you edit it.

A set is a binary classification: every member is either In or Out. Sets can be static, where you tick members by hand, or dynamic, defined by a condition or a top-N rule.

The practical difference is that a dynamic set re-evaluates as the data changes. A set defined as *top 10 customers by sales* stays correct next quarter without anyone touching it; a group does not.

Sets can also be combined — union, intersection, or the members of one that are not in the other — which is how you answer questions like *who bought last year but not this year*. Groups have no equivalent.