Under Questionnaire settings Response options > Students can review ALL responses, the current options are:

• After answering the questionnaire
• After the questionnaire is closed
• Always

A "Never" option would be helpful for peer reviews where the instructor needs to see the name for each student who did the review (so it cannot be anonymous) but does not want students to see each other's results.

There are alternative ways to keep students from viewing all responses which may not work for one complexity or another:

• Use questionnaires for peer evals with the Restrict Access feature to make it unavailable after a certain date/time. This method worked because students were all expected to take the questionnaire at the same time at the end of class at which point the Restrict Access by date/time kicked in. This does not fit for scenarios where a week or more flexible period of time is allowed for students to take the questionnaire as the instructor must manually hide the survey after ensuring all students have completed it. 
• If you do not set a close date, and set "Students can view all responses:" After the questionnaire is closed this would effectively never make the results available as it would never actually be closed. Having a "never" option would be the most logical and efficient way to set this option. It would also be less complicated and more intuitive design.
• Another thought is to provide a score for completion of the survey so you have a way to track in the gradebook who did the peer evaluation. You could make the item weight 0 so it wouldn't count towards the grade. This way, the "Respondent Type" could be set to "anonymous". However, from the instructor's view point, this is more work to be done in the gradebook.

As there is an "Always" option, the opposite of "Never" should be available.