Five form design mistakes that quietly ruin your data
Most data quality problems are not caused in the field. They are built into the form before anyone leaves the office.
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When a dataset comes back messy, the instinct is to blame enumerators or respondents. In our experience, the real culprit is usually the instrument itself. Here are the five mistakes we fix most often.
1. Questions without constraints
If a field accepts any number, someone will eventually type a mother's age as 3 or a household size of 200. Every numeric question should carry a sensible range constraint, with a clear message that tells the enumerator what went wrong.
2. Skip logic that was never tested end to end
Relevance conditions interact. A question that depends on two earlier answers can behave perfectly in nine scenarios and fail silently in the tenth. Before fieldwork, walk through every realistic path in the form, not just the common one.
3. Free text where categories belong
Open text fields feel flexible, but "Amhara", "amhara region", and "AMH" are three different values to your analysis software. Use select questions with a well-designed choice list, and keep "Other, specify" as the safety valve.
4. Labels written for the office, not the doorstep
A question that reads well in a proposal can be unaskable in a live interview. Write labels in the exact words an enumerator should say aloud, and put clarifications in hints rather than cramming them into the question.
5. No unique ID strategy
Duplicate and missing IDs are the most painful cleaning problem because they are discovered last. Build IDs from structure, for example a cascading location code plus an auto-calculated sequence, instead of asking someone to type them by hand.
None of these fixes is glamorous. Together they are the difference between a dataset you defend and a dataset you apologize for.