Development of item bank to measure deliberate self-harm behaviours: facilitating tailored scales and computer adaptive testing for specific research and clinical purposes.
The purpose of this study was to investigate the application of item banking to questionnaire items intended to measure Deliberate Self-Harm (DSH) behaviours. The Rasch measurement model was used to evaluate behavioural items extracted from seven published DSH scales administered to 568 Australians aged 18-30 years (62% university students, 21% mental health patients, and 17% community members). Ninety four items were calibrated in the item bank (including 12 items with differential item functioning for gender and age). Tailored scale construction was demonstrated by extracting scales covering different combinations of DSH methods but with the same raw score for each person location on the latent DSH construct. A simulated computer adaptive test (starting with common self-harm methods to minimise presentation of extreme behaviours) demonstrated that 11 items (on average) were needed to achieve a standard error of measurement of 0.387 (corresponding to a Cronbach׳s Alpha of 0.85). This study lays the groundwork for advancing DSH measurement to an item bank approach with the flexibility to measure a specific definitional orientation (e.g., non-suicidal self-injury) or a broad continuum of self-harmful acts, as appropriate to a particular research/clinical purpose.
School of Social Sciences and Psychology, University of Western Sydney, Penrith, New South Wales, Australia.
Shane
S
Latimer
School of Social Sciences and Psychology, University of Western Sydney, Penrith, New South Wales, Australia. Electronic address: t.meade@uws.edu.au.
Tanya
T
Meade
Department of Rehabilitation Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, UK.
Alan
A
Tennant
D000293:Adolescent; D000328:Adult; D001315:Australia; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D008960:Models, Psychological; D011569:Psychiatric Status Rating Scales; D016728:Self-Injurious Behavior / Q000175:diagnosis* / Q000523:psychology*; D059020:Suicidal Ideation; D011795:Surveys and Questionnaires; D055815:Young Adult
Deliberate self-harm; Non-suicidal self-injury; Rasch measurement; Self-harm