How do you make a survey ask only the questions that apply?

Put conditions on questions and sections so they appear only when earlier answers make them relevant. A long questionnaire then behaves like a short one for each respondent, and the data comes back without meaningless answers to inapplicable questions.

Video: Adding Conditionality to Surveys on YouTube

Why this matters

Conditionality is not just convenience. A form that asks every question of everyone produces data you cannot analyse, because a blank and a genuine "not applicable" look identical. It also lengthens interviews, which lowers quality on the questions you actually cared about. Getting the logic right is one of the highest-return things you can do to a national form before it is deployed to hundreds of enumerators.

How to do it

  1. Identify the branch points in your questionnaire, where whole groups of questions apply only sometimes.
  2. Set a condition on the question or section, based on the answer to an earlier question.
  3. Put conditions on sections rather than on each question when a whole block is involved.
  4. Preview the survey and walk every branch, including the paths you expect to be rare.
  5. Remember when analysing that a skipped question is empty by design, and interpret nulls accordingly.

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