Dementia Knowledge Assessment Scale: Development and Preliminary Psychometric Properties.

OBJECTIVES: To develop a reliable and valid dementia knowledge scale to address limitations of existing measures, support knowledge evaluation in diverse populations, and inform educational intervention development. DESIGN: A five-stage, systematic scale development process was employed to construct and assess the psychometric properties of the Dementia Knowledge Assessment Scale (DKAS). SETTING: Data for the study were generated in an online environment and during clinical dementia care placements from Australian (n = 1,321) and international respondents (n = 446). PARTICIPANTS: Volunteers from a dementia-related massive open online course (n = 1,651), medical students on clinical placement in a residential aged care facility (n = 40), and members of the Australian health workforce (n = 76). MEASUREMENTS: Psychometric properties of the DKAS were established using a literature review to assess the veracity of scale items, respondent feedback during pilot testing, a Delphi study with dementia experts, construction and review by an expert panel, evaluation of item difficulty, item-total and interitem correlations. Principal components analysis (PCA) was also performed along with measures of test-retest reliability, internal consistency, construct validity, and concurrent validity. RESULTS: The pilot DKAS was reduced from 40 to 27 items during analysis. PCA identified four distinct and interpretable factors. The revised DKAS displays high levels of test-retest reliability; internal consistency; and preliminary construct, concurrent, and factorial validity. CONCLUSION: The 27-item DKAS is reliable and shows preliminary validity for the assessment of knowledge deficiencies and change in those who provide care and treatment for people with dementia.