Is there any way for me to turn previous quizzes into quiz banks for future use? For some reason, about half of my previous quizzes appear as quiz banks but the other half don't and I don't know how to add the rest.
The method used to get question banks created would be to create a quiz export where the quizzes reside, then import that newly created export .zip file, as a QTI import, back into the course. This will most likely duplicate the quiz, but you can deleted the duplicated quiz and keep the question bank. In addition, since there are quizzes that already exist within the course I would suggest selecting: "Overwrite assessment content with matching IDs".
I would also recommend testing this in either your test or beta environment or in a development course.
For information on How do I export Quiz content? click on the link.
What does the Course Import tool do?
You can also reference this question Re: How to add questions from a quiz to a question bank? for more assistance.
There isn't a quick and easy way; however, you can export the quizzes and then import them into the same course or a different course. That should create a quiz and question bank.
How do I export quiz content from my course?
How do I import quizzes from QTI packages?
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