An interview is a conversation with stakeholders to elicit or validate needs and requirements.  An interview may include one or more stakeholders.  The interview may also involve a question and answer session used to discover other potential stakeholders and any discrepancies between needs; the high-level requirements derived from those needs; and the resulting detailed requirements.  Interviews facilitate obtaining approval from stakeholders on their needs, requirements, and any changes to them.
Advantages :
• Generally easy, because it can be done with minimal preparation.
• Interviews of individuals and small groups require less planning and scheduling effort than large workshops.
• Interviews of individuals and small groups require less stakeholder commitment than large workshops.
• Interviews provide an opportunity to explore or clarify topics in more detail.
Disadvantages :
• The questions used in the interview may reflect the interviewer’s preconceived ideas, which can influence the responses.
• For projects with a large number of stakeholders the interviews technique can be time-consuming and inefficient.
• Conflicts and inconsistencies between stakeholder information need to be resolved in additional interviews.
• This technique does not allow different stakeholders to hear and elaborate upon the information being relayed.
Formal Interview Process Steps :
1. Identify stakeholders to be interviewed
2. Obtain a general understanding of the customers business
3. Develop interview questions using open-ended questions
4. Set meeting time and location for the interview
5. Provide a set of questions to interviewees prior to the interview (if they will need to prepare for the interview)
6. Use one or more Recorders to accurately preserve results of the interview
7. Provide results to interviewees for confirmation of content
Informal Interview Process Steps :
1. Identify stakeholders to be interviewed
2. Obtain a general understanding of the customers business
3. Develop interview questions (for interviewer’s use only) to make sure certain questions are answered during the session
4. Set up a casual meeting or telephone conversation time for the interview.
5. Takes handwritten notes during the interview; avoid using electronic data capture.
6. Provide results to interviewee for confirmation of content
Sample Interview Questions :
• What would it look like?
• What would convince you?
• What have you already tried?
• Why now?
• What will you settle for?
Interview Leader Role :
The Interview Leader may be responsible for identifying the stakeholders or by working with the appropriate project team member to get the list of stakeholders.  The Interview Leader is responsible for preparing questions ahead of the scheduled meeting and distributing the questions to the stakeholder or stakeholders.  The leader is also responsible to either record the notes or schedule a recorder to attend the meeting to record information discussed in the meeting and any decisions resulting from the meeting.
Recorder :
The recorder is responsible for recording the information discussed in the interview and any decisions resulting from the meeting.  In informal interviews the leader is also the recorder.
Stakeholder :
The stakeholder is responsible for providing their needs, expectations, priorities, and constraints.  They also validate the results of the interview.
Related Articles:
1. Interview Technique : http://directutor.com/content/interview-technique-requirements-gathering-techniques
2. Survey Method: http://directutor.com/content/survey-method-requirements-gathering-techniques
3. Joint Application Development (JAD) Technique : http://directutor.com/content/joint-application-development-jad-technique