Every question, sub-question, and answer option in LimeSurvey has a short identifier — its code:
Q001. LimeSurvey assigns these automatically; you can rename them.SQ001, SQ002.A001.You can ignore codes entirely for a simple survey. They matter the moment you use anything that refers to an answer: piping ({name}), conditions, validation equations, equation questions — and they become the column names when you export responses for analysis.
By default the editor hides codes. There are two ways to turn them on:
With codes shown, each question in the Structure sidebar gets a code badge next to its name (Q001, Q002…), and on the canvas each sub-question shows its code (SQ001, SQ002…) in a small box next to the row.
Q001 to age makes every expression that uses it readable — {age} instead of {Q001}.Codes must be unique within the survey and are kept short — letters and numbers. If you plan to reference a question in logic or text, rename its code before writing the expressions; expressions refer to codes by name, so renaming afterwards means updating every expression that uses the old one.
Hello {firstname} shows the answer to the question coded firstname.Q001_SQ001; an answer option by its code, e.g. A001.