What is the difference between open and closed questions in requirements elicitation?

Open questions (What/Why/How…) invite broad, detailed answers for exploring; closed questions get a single word or pick-from-list answer for confirming and quantifying.

Open questions:

• Broad and can be answered in detail
• Start with W-words (What, Why, How, When, Where, Who)
• Example: "What do you think about this product?"
• Use for: Exploring needs, understanding context, getting detailed feedback

Closed questions:

• Narrow in focus
• Usually answered with a single word or pick from limited multiple-choice options
• Example: "Are you satisfied with this product?" → Yes/No/Mostly/Not quite
• Use for: Confirming understanding, getting specific data, surveys

Best practice: Start with open questions to explore, then use closed questions to confirm and quantify.