Piping

What piping is for

Piping makes a later question refer to an earlier answer by name instead of by description. The difference is small on paper and large in practice:

• Without piping: "How satisfied were you with the service you selected?"
• With piping: "How satisfied were you with bulky waste collection?"

The second is easier to answer accurately, because the respondent does not have to hold their previous answer in their head, and it reads as though the survey is paying attention. It also removes a whole class of ambiguity in surveys where several selections are in play.

How it is written

In NumoForms a pipe is a token of the form {{question_id}}, placed in a question title, a description, or an inline heading. At display time it is replaced with the answer that respondent gave to the referenced question.

The failure case is handled, which is the part that matters. If the referenced question was skipped, left blank, or hidden by a conditional logic rule, the token renders as "your answer". A respondent never sees a raw {{q_7}} on screen — which is the single most common way piping embarrasses people on tools that do not degrade gracefully.

A worked example

1. Q1 "Which service are you telling us about?" → respondent picks "Library".
2. Q2 title: "Thinking about {{q1}}, how easy was it to get what you needed?" → renders as "Thinking about Library, how easy was it to get what you needed?"
3. Q3 description: "Anything else about {{q1}} we should know?"

If Q1 is optional and the respondent skips it, Q2 reads "Thinking about your answer, how easy was it to get what you needed?" — clumsier, but a complete sentence that nobody has to decode.

Common mistakes

• Grammar that only works for one answer. Piping inserts the option label verbatim. If your labels are "Bins", "Recycling" and "Bulky waste collections", write question text that works with all of them — "How satisfied were you with {{q1}}?" rather than "How satisfied were you with the {{q1}} service?", which will read "the Bulky waste collections service".
• Piping free text into a public-facing screen. Whatever the respondent typed comes back at them. That is fine for their own screen and a bad idea anywhere it might be shown to someone else.
• Piping personal data into a survey you have called anonymous. Echoing a name back proves the name is stored. See anonymous survey.
• Over-piping. Three pipes in one sentence stops reading as attentive and starts reading as a mail merge. One per question is usually plenty.
• Piping a multi-select answer without checking. If the earlier question allowed several answers, the pipe returns several, and your sentence has to survive that.

Related but not the same

Carry-forward — showing only the options a respondent selected earlier as the option list of a later question — is a different mechanism from text piping, though the words are often used loosely for both. Piping in NumoForms substitutes text; it does not rewrite an option list.

Hidden fields are also values carried through a survey, but they come from the link rather than from an answer, and they are not displayed.

In NumoForms

Piping and logic are designed together: hide a question with a rule and any pipe pointing at it degrades to "your answer" rather than breaking the sentence. Both are covered in full on the conditional logic feature page, and the question types you are most likely to pipe from — closed-ended choices and short text — are listed on the question types page.