If you mean something like assigning a star rating for good or bad, there isn't anything standard in Zotero. You could create individual tags "star_1", "star_2" and so on, but there are some caveats: 1. If this is for a group, you cannot distinguish the tags by user 2. The same item could be assigned multiple star ratings since tags are not mutually exclusive
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1. If this is for a group, you cannot distinguish the tags by user
2. The same item could be assigned multiple star ratings since tags are not mutually exclusive