Powerful Questions: How to Get the Examples Out of People

The BDD conversation depends on getting concrete examples out of people who are used to describing rules. Most people, asked what a system should do, answer with a generalisation, because generalisations are how requirements are normally discussed. The examples have to be drawn out, and the phrasing of the question does most of the work.

Open questions get information

A closed question invites agreement. So anything over 500 needs approval, right? gets a yes, and the yes carries no information about whether the number is 500, whether it is inclusive, or whether the questioner and the answerer had the same rule in mind.

The open form of the same question gets a fact. What is the largest withdrawal that goes through without anyone approving it? has to be answered with a number, and the number can be wrong in a way that is visible.

The question that does the most work

Can you give me an example?

It converts a rule into an instance, and it is almost always worth asking even when the rule seems clear. A stakeholder who cannot produce an example of a rule they have just stated has usually stated a policy rather than a behaviour, and the behaviour is still unspecified.

The follow-up matters as much: and what should happen then? A great many requirements are stated as conditions with the consequence left implied.

Finding the cases nobody mentioned

Requirements are underspecified at boundaries, so the productive questions point there.

What happens at exactly the threshold? Almost every numeric rule has an off-by-one ambiguity nobody has resolved.

What happens when the expected thing does not? Zero, empty, negative, expired, duplicated and simultaneous are where rules break. The pending-transaction case in most overdraft rules is found by exactly this question.

Has this ever gone wrong? People who work with a system daily remember specific incidents, and an incident is an example with the ambiguity already resolved by reality.

Questions to avoid

Do you want it to work properly? and its relatives invite a yes that means nothing.

Should it be fast? asks for a value judgement instead of a threshold. How long is too long? asks for the number.

Is that everything? closes a conversation that was producing information. What else could happen here? keeps it open, and is usually where the third scenario comes from.

Why this is a documented part of the practice

The connection is historical as well as practical. BDD’s origins run through an interest in how wording shapes thinking, and the observation that a coaching question phrased one way produces a different answer from the same question phrased another. The examples on a whiteboard are downstream of the questions that produced them, so the questions are part of the method rather than a soft skill layered on top.

Asking without leading

The risk in getting good at this is asking questions that contain their own answer. Presumably anything over 500 needs approval? is a closed question wearing an open question’s clothes, and a stakeholder who is unsure will agree with it rather than admit they had not decided.

The correction is to make the ignorance real. I do not know where the line is here, what should it be? invites a decision rather than a confirmation, and it makes it socially possible to answer “we have never decided”, which is frequently the true answer and always the useful one.

When the answer is that nobody knows

This happens often, and treating it as a failure of the meeting is a mistake. A rule nobody has decided is a decision that has been quietly deferred to whoever writes the code, and surfacing it is the most valuable thing a conversation can do.

Two responses work. Take the decision in the room if someone present can, which is faster than anyone expects. Otherwise write the example with the question in place of the value, leave the scenario failing, and name who has to answer. A visibly unfinished specification is honest; a specification completed by guessing is not, and the guess becomes indistinguishable from an agreement within a week.