Interviewing is a systematic approach to eliciting requirements. You can interview an individual or a group of people, in a formal or informal setting. You ask questions relevant to the project and document the responses.

Interviewing should not be the only technique you use to elicit requirements. You will not know all the questions you need to ask. That is why I am a big fan of the Event/Response method. The flow of that methodology creates the questions you will need to ask to ferret out all of the requirements.

In a structured interview, you have a predefined  set of questions. These will be based on how much you already know about the area under study. Here are some sample interview questions:

• What are the business objectives for this project?
• What are your biggest challenges?
• What worries you about this project?
• Who is impacted (good or bad) by this project?
• How are they impacted?
• Are their known changes or projects that impact this one?
• What business processes are impacted?

When interviewing, avoid “yes or no” questions and pay careful attention to the answers. They usually will led to follow up questions that are not on your script. Be prepared to deviate from the script if necessary.

In an unstructured interview, topics are discussed in an open-ended way. You don’t have a script, so the answers are used to spring-board into subsequent questions.

If possible, you should establish in advance a trust and rapport with the interviewee. This will make them more comfortable to be open and honest with you.