Checklist design is input-type design. Every question you ask chooses a data shape - and that shape decides how reliably auditors can answer it, how fast, and how defensibly the answer survives review. Here is the toolkit, in field order.
The judgement fields
Start with conformance - Compliant, Non-Compliant (Critical/Major/Minor), Observation, or N/A - for items where the auditor makes a graded judgement. It is the workhorse of inspection checklists and the basis of non-conformance classification. Boolean (yes/no) covers the simple check; numeric ratings (1-10) suit subjective quality scales; dropdown and multi-select cover controlled vocabularies.
The evidence fields
Where a check must stand up later, capture evidence, not just opinions. Image captures photos straight from the camera - the single highest-integrity input type for proof of condition. File upload accepts documents - certificates, calibration logs, delivery notes. Location tags the check with GPS; signature captures sign-off. QR and barcode scanning turns asset identification (which extinguisher? which batch? which vehicle?) into a one-second scan instead of a typed serial number.
The measured fields
Date, time, and datetime pin events to the calendar - last calibration, expiry, time of arrival. Currency records monetary values - cash verification, damages, invoices. Tally is the quiet hero: a tap-to-count counter for stock, people, or incidents where auditors were previously handwriting tallies. Numeric fields exist for machine readings - temperature, pressure, weight - and calculation fields compute derived values from other answers automatically, so totals can never be arithmetic errors.
The structure fields
Repeating groups let an auditor duplicate a sub-form - one block per vehicle, per row, per employee - without editing the template. Matrix lays related sub-questions out in a grid, rating several attributes of one subject in a single screen. User picker selects a person from the org directory - witness, custodian, interviewee. And instruction items are labels only: they convey guidance, carry no input, and can be used as section intros.
The two most misused types
Rich text, and free text more broadly: invaluable for genuine narrative, catastrophic as a default for everything - it is where interpretation and typos live. And voice: transcripts are useful, but a dedicated audio recording with a hard duration cap is what actually captures tone and context that typing destroys. Use both intentionally, rarely, and audit them accordingly.
Almost every checklist is achievable with a small, deliberate subset. Choose each field for the question it answers and the evidence it preserves, and your checklists will be faster, cleaner, and harder to argue with.