A common measurement scale for self-report instruments in mental health care: T scores with a normal distribution
This article is a preprint and has not been certified by peer review [What does this mean?].
Author(s) / Creator(s)
de Beurs, Edwin
Oudejans, Suzan
Terluin, Berend
Abstract / Description
The diversity of measures in clinical psychology hampers a straightforward interpretation of test results, complicates communication with the patient, and constitutes a challenge to the implementation of measurement-based care. In educational research and assessment, it is common practice to convert test scores to a common metric, such as T scores. We recommend to apply this also in clinical psychology and propose and test a procedure to arrive at T scores approximating a normal distribution, that can be applied to individual test scores. We established formulas to estimate normalized T scores from raw scale scores by regressing IRT-based theta scores on raw scores. With data from large population and clinical samples, we established crosswalk formulas. Their validity was investigated by comparing calculated T scores with IRT-based T scores. IRT and formulas yielded very similar T scores, supporting the validity of the latter approach. Theoretical and practical advantages and disadvantages of both approaches to convert scores to a common metric and alternative approaches are discussed. Provided that scale characteristics allow for their computation, T scores will help to better understand measurement results, which makes it easier for patients and practitioners to use test results in joint decision-making about the course of treatment.
Keyword(s)
IRT T scores percentile ranks common metric clinical normsPersistent Identifier
Date of first publication
2022-03-30
Publisher
PsychArchives
Is version of
Citation
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Manuscript.pdfAdobe PDF - 403.47KBMD5: 05f773f77eff1680bf0d52c734a86494Description: Manuscript
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Author(s) / Creator(s)de Beurs, Edwin
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Author(s) / Creator(s)Oudejans, Suzan
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Author(s) / Creator(s)Terluin, Berend
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PsychArchives acquisition timestamp2022-03-30T08:37:50Z
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Made available on2022-03-30T08:37:50Z
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Date of first publication2022-03-30
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Abstract / DescriptionThe diversity of measures in clinical psychology hampers a straightforward interpretation of test results, complicates communication with the patient, and constitutes a challenge to the implementation of measurement-based care. In educational research and assessment, it is common practice to convert test scores to a common metric, such as T scores. We recommend to apply this also in clinical psychology and propose and test a procedure to arrive at T scores approximating a normal distribution, that can be applied to individual test scores. We established formulas to estimate normalized T scores from raw scale scores by regressing IRT-based theta scores on raw scores. With data from large population and clinical samples, we established crosswalk formulas. Their validity was investigated by comparing calculated T scores with IRT-based T scores. IRT and formulas yielded very similar T scores, supporting the validity of the latter approach. Theoretical and practical advantages and disadvantages of both approaches to convert scores to a common metric and alternative approaches are discussed. Provided that scale characteristics allow for their computation, T scores will help to better understand measurement results, which makes it easier for patients and practitioners to use test results in joint decision-making about the course of treatment.en
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Publication statusother
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Review statusnotReviewed
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Persistent Identifierhttps://hdl.handle.net/20.500.12034/5063
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Persistent Identifierhttps://doi.org/10.23668/psycharchives.5665
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Language of contenteng
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PublisherPsychArchives
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Is version ofhttps://doi.org/10.1027/1015-5759/a000740
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Is related tohttps://www.psycharchives.org/handle/20.500.12034/5060
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Is related tohttps://www.psycharchives.org/handle/20.500.12034/5061
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Is related tohttps://www.psycharchives.org/handle/20.500.12034/5062
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Keyword(s)IRTen
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Keyword(s)T scoresen
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Keyword(s)percentile ranksen
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Keyword(s)common metricen
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Keyword(s)clinical normsen
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Dewey Decimal Classification number(s)150
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TitleA common measurement scale for self-report instruments in mental health care: T scores with a normal distributionen
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DRO typepreprint