An open-ended question is one that puts the least restrictions over the answer to a select option-list. For example, an open-ended question to assess the thoughts would be: What do you think about most often? You can already notice, it is impossible to ask an absolute-open ended question.  For the purpose of the Research Workshop, the College of Physicians and Surgeons states:  Open-ended questions elicit detailed responses and provide no preselected options. These types of questions are the hallmark of qualitative research.   Also, learn the advantages of open-ended questions. 

What are the advantages of open-ended questions? During the clinical assessment, open-ended questions are always preferred to close-ended questions. there are several advantages to the open-ended questions.  If you still don't know What are Open-Ended Questions? Open-ended questions allow patients to start talking about themselves and puts them at ease as they have the floor.  Allows you time to think and plan areas of questioning as you assess their style and content of the response. Allows a period of non-verbal response from interviewer; listening and facilitating.  >> Just slight info: To Have the floor means to have the right or opportunity to speak in a group, especially at a formal event or gathering.  Please, Dr. Dunstaple, your colleague has the floor. You'll have the opportunity to reply when he has finished speaking.