Your school can deliver only the number of intervention places that fit its trained staff, suitable rooms, shared timetable windows and the dosage each pupil needs.
Calculate the weekly bottleneck first. Divide those usable sessions by the sessions each group needs, then multiply complete groups by a safe group size. Do not count spare fragments.
This guide is for mainstream schools in England and is accurate on 4 August 2026. Capacity planning supports, but does not replace, individual assessment and professional judgement.
Why test intervention capacity now?
Summer planning offers a rare chance to put September's provision beside the actual staff timetable. A worthy intention is not yet a session, even when highlighted in a calming colour.
The SEND Code of Practice describes SEN support as a graduated cycle of assess, plan, do and review. Capacity matters because the planned support must reach the pupil before it can be reviewed.
The EEF's current selecting-interventions guidance says targeted support should complement, not replace, high-quality teaching. It should be structured, matched to need and implemented well.
No material official development in the previous 72 hours changed that position. The useful current context remains careful workforce deployment and implementation, not a new national quota.
Use the four-constraint capacity model
Define one intervention model before counting places. Record its purpose, entry criteria, group-size range, session length, weekly frequency, planned duration and review measure.
Then count four constraints for the same week. Mixing an annual pupil list with a Tuesday room timetable creates arithmetic with impressive confidence and very little practical use.
- Need and dosage: which pupils currently match the purpose, and how many sessions does each complete cycle require?
- Trained staff: how many delivery slots remain after preparation, liaison, recording, review and other protected duties?
- Suitable rooms: how many matching slots have a space that is available, accessible and appropriate for the activity?
- Pupil timetable: how many shared windows avoid unacceptable loss of teaching, important routines or another required provision?
Usable weekly sessions equal the lowest of the staff, room and pupil-timetable totals. The needs-led dosage and safe group size then convert those sessions into complete places.
A worked weekly capacity example
This fictional example is arithmetic, not a recommended programme. A structured six-pupil group needs two 30-minute sessions each week with a trained teaching assistant.
After preparation and recording time, the member of staff has eight delivery slots. The suitable room has six. Pupils share five acceptable timetable windows. Five is the bottleneck.
Each group needs two sessions, so five weekly slots support two complete groups. Four slots are committed, one remains for recovery, and planned capacity is 12 places.
If 15 pupils match the current entry criteria, the gap is three places. The answer is not to call an incomplete third group capacity, or to enlarge groups without checking the model.
Review the unmet need with relevant teachers and leaders. Options may include another trained slot, a different suitable time, a second delivery cycle, or a better-matched form of support.
Build one capacity table for each provision
| Field | Record | Decision |
|---|---|---|
| Purpose | Barrier, intended outcome and entry criteria | Who the model is for |
| Dosage | Minutes, sessions, weeks and complete cycle | Sessions needed per place |
| People | Named role, training, preparation and cover risk | Usable staff slots |
| Space | Suitable room and matching availability | Usable room slots |
| Timetable | Shared pupil windows and protected learning | Usable pupil slots |
| Demand | Eligible pupils, assigned pupils and waiting review | Capacity gap or spare places |
| Delivery | Planned, delivered, missed and recovery sessions | Whether capacity became provision |
| Review | Evidence, pupil and parent views, judgement and action | Whether to sustain, adapt or stop |
Separate theoretical, planned and delivered capacity
Theoretical capacity assumes every possible slot works. Planned capacity uses complete cycles and leaves an explicit response to foreseeable disruption. Delivered capacity counts what ran.
Track the reason when a session is missed: staff absence, cover, room displacement, timetable clash, pupil absence or a deliberate professional decision are not the same problem.
Use a rolling review rather than one dramatic end-of-term percentage. Repeated cancellations may require structural action; one exceptional week may require only a sensible recovery plan.
The 2025 EEF teaching-assistant guidance also stresses preparation and training. An adult who appears free on a timetable is not automatically ready to deliver a structured programme.
The connected-data review
Consider a fictional composite school with 12 planned communication-group places. The schedule is full, so the provision map initially suggests that demand and capacity match.
Session records show one group regularly loses its room. Attendance shows three pupils often miss the replacement slot. Outcome evidence is mixed because expected dosage was not received.
The professional question changes from “Do we need another group?” to “Can we protect the room and offer a timetable window these pupils can access?” The action is a joint schedule review.
Provision, room, attendance and outcome data reveal a delivery problem. They do not prove why a pupil was absent, whether the programme is effective, or what support the pupil needs next.
What capacity data cannot prove
A waiting list does not by itself prove that one named intervention is right for every pupil. Empty places do not prove low need. Full groups do not establish that support is effective.
Capacity data cannot diagnose a need, decide SEN status, alter an EHC plan or replace pupil and parent views. It cannot turn correlation between participation and progress into causation.
Do not remove support merely to make demand fit the table. Use the graduated approach, relevant professional advice and the school's duties when deciding what provision is called for.
How Student Radar supports the workflow
Student Radar's Intervention Planner records an intervention's aim, cohort, schedule, assigned staff and room, pupils, sessions and review.
The Provision Map keeps planned support visible by pupil or provision. It helps a SENCo compare assigned demand with the delivery model behind it.
Outcome Tracking keeps evidence and professional judgements beside the provision. None of these views decides who should receive support.
Next actions for the SENCo
- List each provision's purpose, entry criteria, dosage and safe group-size range.
- Count trained staff, suitable room and shared pupil-timetable slots for one normal week.
- Use the lowest slot total, then count only complete delivery cycles.
- Compare planned places with eligible, assigned and awaiting-review pupils.
- Record preparation, review and recovery time instead of treating it as spare capacity.
- Track why sessions do not run and decide who owns structural action.
- Review delivery and outcomes on a named date, including pupil and parent views.
Use the costed provision map guide to add transparent resource assumptions without confusing cost with capacity.
Then use the Assess, Plan, Do, Review evidence guide to decide what would change the next decision.
To see the connected planning workflow in context, request a focused Student Radar walkthrough.
Sources and further reading
- SEND code of practice: 0 to 25 years, Department for Education and Department of Health and Social Care, published 11 June 2014; GOV.UK page updated 12 September 2024.
- Selecting Interventions for pupils with SEND, Education Endowment Foundation, current resource checked 4 August 2026; intervention tool uploaded 10 April 2025.
- Deployment of Teaching Assistants, third edition, Education Endowment Foundation, published 26 March 2025.
- Special Educational Needs in Mainstream Schools, Education Endowment Foundation, published 20 March 2020.
- Strategic workforce planning for schools and trusts, Department for Education, published 4 December 2025.