Explain an invalid optional answer without making it compulsory

What to change

Agree that an optional question remains optional after an error, while any supplied value still receives appropriate format checks.

A worked example

Illustrative example

An optional organisation website rejects an incomplete address. The visitor can either provide the complete address or clear the field and continue.

How to check the result

Accept when the interface accurately offers both recovery routes and does not change the original requirement after a failed attempt.

A mistake to avoid

An error phrased as Enter your telephone number accidentally turns an optional question into a perceived requirement.

Your action checklist

Use these checks to prepare a discussion with your team or supplier. Tick a check when you have recorded the decision or evidence, rather than when a feature has simply been promised.

Decisions to recordEnter an invalid fictional value in an optional telephone or website field and submit. Read whether the message explains that correction or removal is possible.Clear the field completely and submit again. Ask the supplier to check that stale validation or hidden whitespace cannot keep the empty answer in error.Return to enter a valid value and repeat the submission. Confirm both permitted routes work and the receiving system interprets an empty answer consistently.

Evidence, open questions and decisionsNext action and responsible role

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