How OMNIA uses evidence.

MetaSENse is the most comprehensive SEND-specific intervention evidence base currently available. Built from systematic review and meta-analysis of 467 intervention studies involving 58,721 pupils, it identifies which interventions work, for which specific need types, and at what level of evidence quality.

The most important finding: the same intervention can have a positive effect for one SEND need type and no effect — or a harmful effect — for another. OMNIA applies this need-specificity principle to every recommendation it makes.

The EEF Toolkit synthesises findings from nearly 3,000 robust studies, rating pedagogical approaches by effect size — the additional months of progress a pupil makes compared to the average.

OMNIA uses the EEF Toolkit for the cross-cutting approaches that benefit SEND pupils alongside all learners. The most important finding for SEND practice: unstructured TA support has an effect size of just +1 month — and in some models actually widens the attainment gap. OMNIA flags unspecified TA provisions and requires specificity before a plan can be finalised.

Two specific EEF guidance reports directly inform OMNIA's recommendations: Special Educational Needs in Mainstream Schools, and Making Best Use of Teaching Assistants.

The TA deployment guidance is among the most important findings in SEND practice: structured, planned TA interventions significantly outperform reactive support. A TA following a specific programme, delivering targeted intervention, reviewing impact regularly — this is what works. OMNIA's provision map enforces this standard.

Hattie's Visible Learning is the largest synthesis of educational evidence ever conducted — 1,800+ meta-analyses covering over 300 million students. It provides effect sizes for 250+ educational influences, allowing direct comparison of what works most.

OMNIA uses Hattie's hinge point (d = 0.40) as a benchmark: approaches above this point exceed the effect of a typical year of schooling. OMNIA's highest-confidence recommendations are those rated strong by MetaSENse, the EEF, and Hattie simultaneously — what OMNIA calls 'triple-verified' strategies.

An honest note: Hattie's methodology has attracted legitimate academic criticism, including questions about averaging effect sizes across studies of different quality and context. OMNIA uses Visible Learning as one lens among several — not as the sole authority.

Peps McCrea's High Impact Teaching series synthesises cognitive science and educational research into practical classroom principles. His work on memory, motivation, and expert teaching is directly relevant to how OMNIA frames provision recommendations for SEND pupils.

Specifically: spaced practice, retrieval practice, worked examples, and explicit instruction — all of which feature in OMNIA's strategy library — are grounded in the cognitive science research McCrea synthesises in Memorable Teaching and Lean Lesson Planning.

For SEND pupils, these principles are particularly powerful: cognitive load is higher, working memory is often more limited, and the gap between knowledge acquisition and knowledge retention is wider. Recommendations informed by cognitive science close that gap more reliably than general classroom support.

The DfE commissioned six rapid evidence assessments in autumn 2024, covering identification, support, collaborative practice, early identification, transition, and teacher preparation for SEND. These are the most current government-commissioned SEND evidence reviews available.

Key findings OMNIA applies: early, standardised identification outperforms teacher judgement alone; structured, fidelity-based interventions outperform general support; co-production with families improves outcomes. All three directly shape how OMNIA generates plans and provision recommendations.

Emotionally Based School Avoidance is one of the fastest-growing referral areas for SENDCos post-pandemic. OMNIA's EBSA guidance draws on the Anna Freud Centre's school-based framework, Bath University's research programme, and NASEN's practice guide.

The evidence is unambiguous: EBSA is anxiety-based, not behaviour-based. Punitive attendance approaches have evidence of harm. Graduated reintegration, CBT-adapted anxiety support, and consistent adult relationships have evidence of benefit. OMNIA will not recommend punitive attendance measures for pupils with EBSA flags.

The study that frames why OMNIA exists. Research examining 242 interventions used across a school cluster found that only 30% had evidence of positive impact, 67% had no published evidence, and 3% had evidence of active harm.

This finding is not cited to criticise schools. SENDCos are working with limited time, limited resources, and limited access to research. The problem is systemic — the research doesn't reach the classroom. OMNIA's purpose is to change that.

The IEE produces systematic reviews applying high methodological standards, particularly for reading difficulties and mathematics difficulties in pupils with SEND. The IEE's work complements MetaSENse with additional rigour on specific high-prevalence need types.