A major study from Durham University and the University of Oxford, published in the Journal of Learning Disabilities, looked at over 540,000 Year 6 pupils across 14,800 schools in England and asked a simple question: which children get identified with a specific learning difficulty, and which get missed?
The answer is uncomfortable. Two children with identical test scores can have very different chances of being identified, depending on who they are and where they go to school. Pupils in high-achieving schools were more likely to be identified than pupils with the same scores in lower-achieving schools, because "underachievement" tends to be judged against the school's average rather than the child's potential. Schools with more children from disadvantaged areas identified fewer pupils, which the researchers link in part to families' unequal access to private assessments.
The pattern holds for who the child is, too. Boys had about twice the odds of being identified as girls with similar maths attainment, and children who speak English as an additional language were substantially less likely to be identified than classmates with the same reading or maths scores. Professor Steve Strand, one of the authors, described the variation between primary schools as huge, with much of it unexplained.
What this means for families
If your child is a girl, speaks English as an additional language, or attends a school where they're "doing okay" against the class average, a genuine difficulty can slip through unnoticed. You know your child best. If the effort going in at home doesn't match the results coming out at school, it is reasonable to ask questions, and an independent assessment looks at your child as an individual rather than against a school average.