| Class | QuestionAction | An enumeration of the possible actions done on a question. |
| Class | QuestionJobType | Values that IQuestionJob.job_type can take. |
| Class | QuestionRecipientSet | The kinds of recipients who will receive notification. |
| Class | QuestionParticipation | The different ways a person can be involved in a question. |
| Class | QuestionPriority | The Priority with a Question must be handled. |
| Class | QuestionSort | An enumeration of the valid question search sort order. |
| Class | QuestionStatus | The current status of a Question. |