SUMMARY EXPERIMENTAL
CLINICAL PSYCHOLOGY
Book Summary year 2020/2021
, 1
Based on Kazdin, A. E. (2010). Research Design in Clinical Psychology.
Allyn and Bacon.
Lecture Page
1 2
2 19
3 31
4 39
5 45
6 52
, 2
Lecture 1 Relevance and
overview________________________________________________
Chapters: 2, 3 and 13
Chapter 2 Internal and external validity
The important concept of plausible rival hypothesis addresses the competing
interpretations that might be posed to explain the findings of a particular study.
Methodology helps rule out competing interpretations. From a methodological
standpoint, the better the design of an investigation, the more implausible it
makes competing explanation of the results.
2.1 Types of validity
The purpose of research is to reach well-founded (i.e. valid) conclusions about the
effects of a given experimental manipulation or intervention. Four categories of
experimental validity are used to evaluate the methodology of a study. These
are:
1. Internal validity: To what extent can the intervention, rather than
extraneous influences be considered to account for the results, changes, or
differences among conditions? So, how well does the intervention work?
Are the changes because of the intervention or just a coincidence?
2. External validity: To what extent can the results be generalized or
extended to people, settings, times, measures/outcomes, and
characteristics other than those included in this particular demonstration?
3. Construct validity: Given that the experimental manipulation or
intervention was responsible for change, what specific aspect of the
manipulation was the mechanism, process, or causal agent? What is the
conceptual basis (construct) underlying the effect?
4. Data-evaluation validity: To what extent is a relation shown,
demonstrated, or evident between the experimental manipulation or
intervention and the outcome? What about the data and methods used for
evaluation that could mislead or obscure demonstrating or failing to
demonstrate and experimental effect?
A decision to maximize one type of validity can be at the expense of others.
Investigators prioritize types of validity and manage potential problem to ensure
that their hypotheses are well tested.
2.2 Internal validity
Independent variables are the experimental manipulation or variable we are
evaluating
to see if it has an effect. Dependent variables are the outcome or measure we
are examining to reflect the impact or effects of the independent variable. In any
study, we wish to draw conclusion about the effects of the independent variable.
When the results can be attributed with little or no ambiguity to the effects of the
independent variable, the experiment is said to be internally valid. Factors or
influences other than the independent variable that could explain the results are
called threats to internal validity.
CLINICAL PSYCHOLOGY
Book Summary year 2020/2021
, 1
Based on Kazdin, A. E. (2010). Research Design in Clinical Psychology.
Allyn and Bacon.
Lecture Page
1 2
2 19
3 31
4 39
5 45
6 52
, 2
Lecture 1 Relevance and
overview________________________________________________
Chapters: 2, 3 and 13
Chapter 2 Internal and external validity
The important concept of plausible rival hypothesis addresses the competing
interpretations that might be posed to explain the findings of a particular study.
Methodology helps rule out competing interpretations. From a methodological
standpoint, the better the design of an investigation, the more implausible it
makes competing explanation of the results.
2.1 Types of validity
The purpose of research is to reach well-founded (i.e. valid) conclusions about the
effects of a given experimental manipulation or intervention. Four categories of
experimental validity are used to evaluate the methodology of a study. These
are:
1. Internal validity: To what extent can the intervention, rather than
extraneous influences be considered to account for the results, changes, or
differences among conditions? So, how well does the intervention work?
Are the changes because of the intervention or just a coincidence?
2. External validity: To what extent can the results be generalized or
extended to people, settings, times, measures/outcomes, and
characteristics other than those included in this particular demonstration?
3. Construct validity: Given that the experimental manipulation or
intervention was responsible for change, what specific aspect of the
manipulation was the mechanism, process, or causal agent? What is the
conceptual basis (construct) underlying the effect?
4. Data-evaluation validity: To what extent is a relation shown,
demonstrated, or evident between the experimental manipulation or
intervention and the outcome? What about the data and methods used for
evaluation that could mislead or obscure demonstrating or failing to
demonstrate and experimental effect?
A decision to maximize one type of validity can be at the expense of others.
Investigators prioritize types of validity and manage potential problem to ensure
that their hypotheses are well tested.
2.2 Internal validity
Independent variables are the experimental manipulation or variable we are
evaluating
to see if it has an effect. Dependent variables are the outcome or measure we
are examining to reflect the impact or effects of the independent variable. In any
study, we wish to draw conclusion about the effects of the independent variable.
When the results can be attributed with little or no ambiguity to the effects of the
independent variable, the experiment is said to be internally valid. Factors or
influences other than the independent variable that could explain the results are
called threats to internal validity.
