13. External Validity

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13. External Validity

• What is meant by the external validity of a
  research design?
• How is research limited in regard to
  generalization to other groups
• of people?
• How does ecological validity help increase
  confidence that an
• experimental will generalize to other research
  settings?
• What is the purpose of replication? What are the
  differences among
• exact, conceptual, and constructive replications?
• What is a participant replication, and when it is
  used?
• What is the purpose of review papers and
  meta-analyses? What are the
• differences between the two?

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External Validity
The extent to which the results of a research
design can be generalized beyond the specific
way the original experiment was conducted.
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Generalization
The extent to which relationships among
conceptual variables can be demonstrated in a
wide variety of people and a wide variety
of manipulated or measured variables.
Generalization Across Participants
Generalization Across Settings
Ecological Validity
Field Experiment
Experimental research designs that are conducted
in a natural environment such as a library, a
factory, or a school.
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Replication
The process of repeating previous research, which
forms the basis of all scientific inquiry.
Conceptual Replication
Exact Replication
An replication that provide information about the
specific conditions under which the original
relationship might or might not be found.
An replication that repeats a previous research
design as exact as possible.
Constructive Replication
Participant Replication
An replication which tests the same hypothesis as
the original experiment, but also adds new
conditions to the original conditions to assess
the specific variables that might change the
previously observed relationships.
An replication that repeat a previous research
design using different participants from a
different population (culture)
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Summarizing and Integrating Research Results
Research Program
Systematic studies throughout conceptual and
constructive replications over a period of time.
Review Papers
A document that discusses the research in a given
area with goals of summarizing the existing
findings, drawing conclusions about the
conditions to other areas of research, and making
suggestions for further research.
Meta-analysis
A statistical technique that uses the results of
existing studies to integrate and draw
conclusions about those studies.