Diagnostic assessment is a type of formative assessment particularly intended to diagnose areas of weakness, or misunderstanding, and strength.

The aim of diagnostic assessment is to reveal an underlying problem in learning or to find out about the learner's ways of learning, in order to help her/him achieve learning aims. This more detailed, in-depth type of formative assessment was called 'taking a closer look' in the original 5-14 assessment guidance. There are many forms of published 'diagnostic tests', but, in the ordinary course of teaching, the teacher's interaction and discussion with a pupil is often the most effective basis for this process.

A type of formative assessment that is used to identify specific learning difficulties and to indicate the nature of the difficulties. Source: Griffin, P. & Nix, P. (1991) Educational Assessment and Reporting: A New Approach, Harcourt Brace Jovanovich, Sydney: 264. See also ' formative assessment'.

A diagnostic assessment identifies a pupil’s underlying strengths and needs in a particular area. Such an assessment may be able to explain why a child is experiencing a specific learning difficulty and can help teachers to evaluate the severity of the problem. This information will prove to be invaluable when devising future teaching programmes.

Designed to provide a detailed assessment of a learner's skills and abilities against the requirements set out in the national standards and national curriculum documents. Results can be used as the basis for the development of the learner's individual learning plan (ILP) and learning programme.