Raising understanding of dementia has become a key focus of international health and social care. An up-to-date, psychometrically sound measure of dementia knowledge that embraces a biopsychosocial perspective is lacking. The aim of this study is to develop and evaluate the psychometric properties of the DK-20, a dementia knowledge questionnaire aimed at unqualified care staff.

Domain and item generation followed recommended measure development procedures. A pilot and large-scale study evaluated the psychometric properties of the measure on a sample of 211 care staff and other dementia professionals.

The final 20-item measure encompasses items based on biopsychosocial dementia knowledge and care-specific knowledge. Acceptable test-retest reliability, marginal levels of internal consistency, and evidence for face, content, and construct validity were demonstrated.

The DK-20 is the first knowledge of dementia measure to be developed specifically for unqualified care staff and has reasonable psychometric properties. It may be used to identify gaps in knowledge, highlighting areas for inclusion in educational interventions.