A child is meaningfully behind when important prerequisite knowledge or skills are no longer strong enough to support the current level. One low score, one difficult chapter, or one slower week does not prove that. The stronger evidence is a pattern: recurring difficulty with material that should already be secure, growing dependence on help, or later topics failing because earlier foundations remain unstable.
Compare the child with the actual demands of the present curriculum rather than with anxiety, siblings, or classmates. Check what they can do independently, what still requires prompting, and whether the gap is narrowing after ordinary teaching and practice. A precise gap can usually be repaired; a vague label such as “behind” is much less useful.
Start with the Parents & Pathways Hub for level and progression, and use the Diagnostics & Recovery Hub to identify the exact prerequisite that needs attention.