Unidimensionality of the Strengths and Vulnerabilities Scales in the Short-Term Assessment of Risk and Treatability (START)

Abstract

The Short-Term Assessment of Risk and Treatability (START) is a 20-item structured professional judgment instrument for assessing dynamic risk in mental health services. Much of the START research literature examines the relationship between Strengths and Vulnerabilities sub-scale total scores and various adverse outcomes including violence. This assumes that the two sub-scales have the psychometric property of unidimensionality i.e. all the items cluster together as a measure of a single construct. Such assumed unidimensionality is a necessary condition for any analyses based on scale "total score" and the widespread use of scores summated in this way in research studies may obscure more specific clusters of items within each sub-scale. This multinational study examined START assessments (n ¼ 685) conducted in four forensic services in Scandinavia and the UK using principal component analysis. It was found that all but three Strengths items (Substance Use, Social Support and Material Resources) and all but four Vulnerabilities items (Substance Use, Social Support, Material Resources and Self care) loaded >0.5 on the expected component. This indicates a unidimensional structure underlying the START and provides empirical support from a large multinational sample for the widespread use of summated Strengths and Vulnerabilities scores in forensic psychiatric risk research.

Reducing Risk for Future Violence From Forensic Psychiatric Patients by Using Critical Factors of the Short-Term Assessment of Risk and Treatability as a Caring Tool

“…By using START as a caring tool for treatment planning and interventions, our results point out items relevant to address to reduce risk of violence. In several studies, this sum is found to have a predictive validity, and we have also found in a previous study that it was a homogeneous construct (Whittington et al, 2022). Of special relevance is that we can describe certain critical factors as more relevant to address in the care planning for reducing risk for future violence.…”

“…Therefore, using the total sum of vulnerability scores should be regarded as a reasonable measure of future risk, especially risk for violence. Furthermore, it has been noted that the sum of vulnerabilities is a unidimensional construct (Whittington et al, 2022). Subsequently, changes over time in total vulnerability score reflect a change in risk for future violence.…”

Effects of Implementing the Short-Term Assessment of Risk and Treatability for Mechanical Restraint in a Forensic Male Population: A Stepped-Wedge, Cluster-Randomized Design

“…Previous research has primarily focused on its validation and predictive ability ( 19 , 20 ). The most recent study focused on summarizing item values as a single concept, primarily for research purposes ( 21 ). To our knowledge, no previous study has highlighted the reduction in mechanical restraint use as an outcome.…”

Risk assessment challenges in a specialized clinic for individuals referred for violent extremism.

“…To inform the formulation of SREs, the START considers a wide range of items (O'Shea & Dickens, 2014), of which the more frequently studied are 20 dynamic items rated both as protective factors ("strengths") and risk factors ("vulnerabilities"). The START distinguishes itself from other risk assessment instruments by its emphasis on dynamic variables, the inclusion of strengths in the assessment process, and its consideration of understudied outcomes such as substance misuse, self-neglect, unauthorized leave, and victimization (Marriott et al, 2017;Whittington et al, 2022). A youth version was developed and validated: the START adolescent version (START-AV; J. L. Viljoen et al, 2012Viljoen et al, , 2014.…”