It depends on the survey mechanism: If you are only selecting scores from 1-5, aren't saying a word, and the minimum unit of aggregation is 10 people, and it's

It depends on the survey mechanism: If you are only selecting scores from 1-5, aren't saying a word, and the minimum unit of aggregation is 10 people, and it's all handled by a third party, you can be truthful. But any time you enter text, nothing is really anonymous. There can still be issues of group identification: If a manager gets far worse scores than their peers, nothing guarantees that higher management will actually do something about the manager, vs believing that they just have a team with bad attitudes, and tell the manager to fire the person that they think si the biggest troublemaker, but if that's the case, chances are you wanted to get out of Dodge anyway.