Chapter 4 –
Research Methods
in Clinical Psych
Copyright © 2014 John Wiley & Sons, Inc. All
rights reserved.
Ways of Generating
Research Hypotheses





Everyday Experience and
Observation
Professional Experience and
Observation
Addressing Applied Problems and
Needs
Previous Research
Theory
Copyright © 2014 John Wiley & Sons, Inc. All
rights reserved.
Relationships Between
Variables



Correlation – the variables are
associated in some way
Moderation – one variable influences
the direction or size of another
Mediation - one variable explains the
relationship between two others
Copyright © 2014 John Wiley & Sons, Inc. All
rights reserved.
Ethics in Research (some
principles)







Institutional approval
Informed consent
Inducements for participation
Deception in research
Debriefing
Humane care for animals
Reporting results
Copyright © 2014 John Wiley & Sons, Inc. All
rights reserved.
Important Concepts to
Clinical Research




Internal validity – controlling for biases
External validity – how representative
and applicable the study is
Statistical conclusion validity – whether
the study was designed in a way to
adequately test hypotheses through
statistical methods
Statistical versus clinical significance
– Effect size
Copyright © 2014 John Wiley & Sons, Inc. All
rights reserved.
Clinical Research Designs

Case Study – detailed description of a
case, which can allow for a great deal
of hypothesis generating
– Down side: many threats to internal
validity making it difficult to generalize

Single case designs A-B (two measures
of symptoms pre and post treatment
– A-B (designs with a number of clients)
– A-B-A (designs with one person at different
time points)
Copyright © 2014 John Wiley & Sons, Inc. All
rights reserved.
Clinical Research Designs

Correlational designs – association of
variables (most common)
– Note even DSM group v control is a
correlational design
– ‘Median splits’ on a particular variable
– Factor analysis – the underlying structure
of a variable
– Mediator v Moderator designs
– Structural equation modeling
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Clinical Research Designs


Quasi-experimental designs –
comparing groups when random
assignment is not available or ethical
Experimental Designs (the ‘gold
standard’ in clinical research) – random
assignment and experimental
manipulation
– Randomized controlled trials (RCT)
Copyright © 2014 John Wiley & Sons, Inc. All
rights reserved.
Clinical Research Designs

Meta-analysis – summarizing several
similar studies through a statistical
analysis
– Effect size – a statistical measure of how
strong the experimental effect is (i.e.,
statistical significance does not say how
strong the effect is, only that it is unlikely
to have randomly occurred)
Copyright © 2014 John Wiley & Sons, Inc. All
rights reserved.
Selecting the Participants


Importance of selecting a
representative sample (age, gender,
SES, ethnicity, etc.)
Sampling strategy – how participants
are chosen/recruited
– Probability sampling – requesting
participants from say, every 10th person in
a neighborhood
– Non-probability sampling – recruiting
through a method that will reach as many
people as possible
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Selecting the Participants

Setting the sample size – making sure
there are enough participants to detect
differences in groups
– Low power
– Sufficient sample size
– Statistical significance
– Clinical significance
Copyright © 2014 John Wiley & Sons, Inc. All
rights reserved.
Selecting the Measures




Self-Report Measures – participant
report.
Informant-Report Measures –
report by someone who knows the
participant
Rater Evaluations – research
assistant rates the participant
Performance Measures – how a
participant does on a task (e.g.,
reaction time or behavioral measure)
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Selecting the Measures




Projective Measures – participant
responses to ambiguous stimuli, which may
reflect the internal state of the participant
Observation of Behavior - coding systems
used to summarize complicated behavior
Psychophysiological Measures – a range
of measures reflecting biological markers
(e.g., heart rate, blood pressure, neural
activity)
Archival Data – Data stored for some other
purpose used for research (e.g., police
records, health care utilization records, and
academic records)
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Psychometric Properties
of the Measures
Reliability



Internal Consistency: How homogeneous the test
items are
Test-Retest Reliability: How stabile over time
scores on a measure are
Inter-Rater Reliability: The consistency of scores
on a measure across different raters or observers.
Validity


Content Validity: How fully and accurately the
measure represents the construct being assessed
Face Validity: How much the measure overtly
appears to be measuring the construct of interest.
Copyright © 2014 John Wiley & Sons, Inc. All
rights reserved.
Psychometric Properties
of the Measures
Validity (cont.)
 Criterion Validity: The association of a
measure with a related criterion
 Concurrent Validity: The association of a
measure with other relevant data measured
at the same point in time.
– Predictive Validity: The association of a
measure with other relevant data
measured at some future point in time.
Copyright © 2014 John Wiley & Sons, Inc. All
rights reserved.
Psychometric Properties
of the Measures
Validity (cont.)
 Convergent Validity: The association
between a measure and either other
measures of the same construct or
conceptually related constructs
 Discriminant Validity: The association
between measures that, conceptually, should
not be related
 Incremental Validity: The extent to which
a measure adds to the prediction of a
criterion beyond what can be predicted with
other measurement data
Copyright © 2014 John Wiley & Sons, Inc. All
rights reserved.