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Introduction to
Clinical PsychologyScience, Practice and Ethics
Chapter 5General Issues in Psychological Assessment
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Stages of Psychological Assessment
Stage I: Planning the Assessment Stage II: Data Collection Stage III: Processing Assessment Data Stage IV: Communicating Assessment
Findings
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Goals of Psychological Assessment
Classification Description Prediction
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Classification
Diagnoses DSM-IV
Criticisms of Diagnoses Implies understanding Association with medical model Variable reliability Negative social stigma
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Diagnoses: Responses to Criticisms
Categorization facilitates research Diagnostic labels can facilitate
treatment Diagnostic labels can facilitate
communication
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Description
Dimensional (as opposed to categorical)
Person by situation Generates research hypotheses Facilitate treatment planning Evaluate treatment outcome
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Prediction
Prediction terms: True positive False positive True negative False negative Sensitivity Specificity
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Prediction
The Base Rate Problem Low base rate problems are difficult to
predict Low base rate problems tend to be
overpredicted (many false positives) Clinical versus Statistical prediction
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Clinical versus Statistical Approaches
Clinical (or subjective) method – clinician constructs a model to explain client’s behavior and predict future behavior
Statistical (or quantitative or actuarial) – people are classified based upon the characteristics they share with others. They are expected to behave the way similarly classified people behave
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Clinical versus Statistical Approaches
Paul Meehl (1954) Clinical versus Statistical Prediction: A Theoretical Analysis and Review of the Literature “in all but one…the predictions made
actuarially were either equal to or superior to those made by the clinician”
Jack Sawyer (1966) Statistical superior to clinical approach to
prediction Clinicians could not improve upon actuarial
prediction
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Responses to Statistical Superiority
Methodologically weak studies Not Expert Judges Findings not cross-validated Poor Ecological Validity
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Counter-arguments Methodologically weak studies
Methodologically weak and strong studies yield consistent findings (actuarial > clinical
Not Expert Judges But those that did yield use expert judges
yielded the same findings (actuarial > clinical) Findings not cross-validated
But those that did cross-validate yielded the same findings (actuarial > clinical)
Poor Ecological Validity But the tasks are not meaningless
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Recent Review Meehl (1957, 1965, 1986) Dawes, Faust, & Meehl (1989) – reviewed
close to 100 studies – actuarial equal to or superior to clinical in every one.
Dawes (1994) House of Cards: Psychology and Psychotherapy Built on Myth
Milner & Campbell (1995) – “ The consensus of opinion is that statistical prediction is more accurate than clinical prediction”
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Clinical Approach: Current Status
Clinical approach is necessary in situations for which no statistical equations have been developed.
Unforeseen circumstances impair the efficiency of the formula.
Rare, unusual events of highly individualized nature are to be predicted.
Clinician as data-gatherer
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Stage II: Data Collection
Interviews Norm-referenced tests Observations Informal assessment methods Life records
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Stage III: Processing
Clinical Judgment Computer assisted assessment
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Clinical Judgment:Threats to Accuracy
Preconceived Notions Confirmation Bias Hindsight Bias Overconfidence
Recall successes Only examining certain types of cases Self-fulfilling prophecy
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Reducing Impact of Biases
Search for alternative explanations Understand the impact of base rates Decrease reliance on memory
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Computer-assisted assessment
Professional time savings Test administration consistency Rapid turnaround time Scoring accuracy Data analysis Special populations
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Communicating Assessment Findings
Goals Address the referral question Improve understanding Impact client Provide a written record A legal document
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Communicating Assessment Findings
Include all relevant information Delete irrelevant or damaging
information Avoid undue generalizations Use behavioural referents Communicate clearly Eliminate biased terms
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Communicating Assessment Findings
Identifying Information Reason for Referral Background Information Behavioural Observations Assessment Results and
Interpretation Summary Recommendations