Field note · 2026-01-28
A single DNA percentage for an outpatient group will not tell you whether people forgot, whether letters went to the wrong address, or whether the clinic cancelled the list and left the code unchanged.
In English outpatient practice, ‘did not attend’ is a residual category. It collects people who did not arrive, people who arrived after the clinic had given up, people whose letters never reached them, and, in some extracts, lists that the hospital itself stood down.
Before anyone writes a reminder campaign, split the column. Ask the PAS administrator for the local codes: patient cancellation under 24 hours, patient cancellation over 24 hours, hospital cancellation, DNA, and ‘could not wait’. If those codes are not used consistently between sites in a group, a comparison chart is theatre.
Day of week still matters. Monday morning ophthalmology lists in some groups show higher DNA after a weekend of reminder texts that landed on Saturday evening. Friday afternoon community clinics show a different pattern: people who work cannot leave, and the DNA looks like disengagement when it is a clash with a shift.
Address quality is unglamorous and decisive. Returned clinic letters should be counted alongside DNA. If the returned-letter pile is thick, a second text reminder will not repair the list. Reception staff usually know this before the operations meeting does.
When we write a DNA study we publish the definitions on page one. We would rather a smaller, honest number than a percentage that cannot be repeated next quarter.