A hand-kept temperature log is useful only when it shows where and when the reading was taken. Copied or backfilled rows do not explain what actually happened.

Standardise the record fields

Include date and time, product or measurement point, device ID, reading and operator. Add a separate field for action when a deviation occurs.

Do not hide missing data

If a reading was missed, do not fill the gap with a later guess. Mark it missing, record the reason and note corrective action.

Compare manual and automatic records. Place a logger at the same location and align its start and end times with the sheet. Use the same point and instrument, then review differences.

Review anomalies. Treat repeated identical values, rounded times or missing actions as prompts to investigate; they do not prove a failure on their own.

If paper remains in use

Identify the operator and instrument, make corrections traceable and assign an owner to follow up missing rows.