The specification is a moving target
The NDTMS dataset specification defines exactly what fields a submission must contain, how they are formatted, and the rules a dataset is validated against. OHID, formerly PHE, updates that specification periodically to reflect changes in policy, reporting priorities, and the treatment system.
For services, the important point is that the specification is not fixed. A dataset that submitted cleanly last year may fail this year, not because the service changed anything, but because the rules did.
Why specification changes break manual exports
Many services still build their NDTMS return from spreadsheets, export macros, or a static template mapped once and rarely revisited. That works right up until the specification changes — and then a field is renamed, a new value is required, or a validation rule tightens, and the export quietly produces records that no longer pass.
Because the break is invisible until submission, it tends to surface at the worst possible moment: on deadline day, when the person who built the original mapping may no longer be at the service. The cost of a static approach is not visible in normal months; it lands all at once when the rules move.
What to check when a new specification is released
When OHID publishes an updated specification, work through the change with your data lead rather than assuming last quarter's process still holds. In particular, review:
- New or renamed fields — anything your export does not currently produce.
- Changed permitted values — code lists that have gained, lost, or renamed options.
- Tightened validation rules — checks that will now reject records that previously passed.
- Changed timing or frequency expectations for TOPs, CIRs, or SIRs.
- Any transitional dates that determine when the new rules take effect.
Building a process that absorbs change
The services that handle specification changes calmly are the ones that do not depend on a single fragile export. They either maintain their mapping deliberately each release, or they use a system where the specification is maintained centrally so the change reaches every service at once.
GreenShoots includes NDTMS specification updates in the subscription and applies them to the dataset it generates and the validation it runs, so a specification change does not become a project for your data lead. Your clinical records stay the same; the mapping between them and the current specification is kept current for you.
A short readiness checklist
Use this whenever a specification update is announced:
- Confirm which submission period the new specification first applies to.
- Identify any new required fields and check your records can supply them.
- Re-run a validation report against the new rules on existing data.
- Brief keyworkers on any change that affects what they record or when.
- Note the change and date in your data governance log for audit.