Assessment measures performance in relation to a particular question or situation but the value of competence assessment lies in its ability to predict likely future performance in a particular activity. In nursing, as in some other safety-critical areas, competence in numeracy can be a matter of life or death so the onus is on assessment procedures to ensure safe practice as far as possible. The assessment of numeracy for nursing should enable candidates to demonstrate that their numeracy is fit for practice, fit for purpose and fit for award. Students at point of registration and qualified staff should be able to demonstrate independence, good critical judgment, proficiency in practice and accountability to relevant stakeholders with respect to numeracy. However, while numeracy is acknowledged to be a key competence for professional practice in nursing, it is poorly conceptualized and understood, and, as a result, likely to be inadequately assessed. Successive studies reveal a lack of proficiency amongst students and registered nurses in the UK and elsewhere, together with efforts to remediate the situation (Sabin 2001).