Introduction to
Clinical Psychology
Science, Practice and Ethics
Chapter 5
General 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
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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:
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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
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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
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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
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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
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Professional time savings
Test administration consistency
Rapid turnaround time
Scoring accuracy
Data analysis
Special populations
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Communicating Assessment
Findings
 Goals
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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
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