Piping
When an answer is missing
What respondents see if a piped question was skipped.
A plain answer pipe inserts an empty string when the referenced answer is missing. This can happen when the earlier question was optional, a branch skipped it, or a follow-up was not answered.
A title such as “Thanks, name!” can therefore become “Thanks, !” if the name was not collected. Write a fallback when the sentence depends on that answer.
Respondent sees
Hello Alice!
Clear the name in this example to see the fallback. The || operator uses the fallback for a
false-like value, so take care with valid numeric zero or a Yes/No answer of No.
Check the route
Can everyone who reaches this field have answered the source question?Choose a fallback
Use wording that still makes sense when the value is absent, or use a conditional expression when the distinction matters.Test the missing case
Leave the source unanswered or take the branch that skips it, then read the resulting text in Preview.Expressions require Essential. On other plans, make the source required when appropriate, or avoid wording that depends on an optional answer.
Required does not guarantee an answer on every route
Consider two branches: Version A asks for a workshop rating, while Version B asks a different question. A shared summary cannot assume Version A's rating exists for everyone. Making that rating required only prevents people who see it from continuing without an answer.
Use a shared source before the split when all respondents need the same summary value. Otherwise, write wording appropriate to each route or handle the missing value explicitly.
Keep valid zero and No answers
For an optional number of visits, zero can mean “I have not visited”. A generic fallback using ||
would replace that zero too. Decide whether you need to distinguish absent, zero and nonzero values
before choosing the expression. Test all three in Preview rather than only a positive number.
Missing inputs also affect calculations. They are not automatically left out of an average, and numeric conversion can treat an empty value as zero. Do not use a fallback of zero unless zero is the meaning you intend. Requiring the inputs, adjusting the route, or showing an alternative sentence can be clearer than displaying a misleading score.
Check the source before changing the formula
If the output is unexpectedly blank, confirm the reference still points to an existing earlier question. Then check the selected part of the answer: a follow-up reason can be blank even when the main score exists, and a specific row or option attribute may not have a value. See choosing what to pipe.