18 - Experimental and Quasi-Experimental Research
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Transcript of 18 - Experimental and Quasi-Experimental Research
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Experimental and Quasi-Experimental Research
KNES 510
Research Methods in Kinesiology
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Experimental Research Tries
Selection of a good theoretical frameworkApplication of appropriate experimental designUse of correct statistical model and analysisProper selection and control of independent variablesAppropriate selection and measurement of dependent variablesCorrect interpretation of results
to Establish Cause and Effect*
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Three Criteria for Cause and Effect
The cause must precede the effect in time
The cause and effect must be correlated with each other
The correlation between cause and effect cannot be explained by another variable
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Reviewing Important Terms
Independent variableDependent variableCategorical variable-(age, sex=not controlled)Control variable-excludeExtraneous variable*
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Types of Validity
Internal validityExternal validityTrade-off between internal and external validitySeries of experiments (studies)*
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Threats to Internal Validity
History-duringMaturationTestingInstrumentationStatistical regressionSelection bias*
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Threats to Internal Validity, contd
Experimental mortalitySelection-maturation interactionExpectancy*
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Threats to External Validity
Reactive or interactive effects of testingInteraction of selection biases and treatmentReactive effects of experimental arrangementsMultiple-treatment interference*
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Controlling Threats to
Randomization
Internal ValidityReal randomization
Matched pairs (but not matched groups)
Randomizing treatments or counterbalancing
PlacebosBlind setupsDouble-blind setups*
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Uncontrolled Threats to
Reactive effects of testingInstrumentationExperimental mortality
Internal Validity*
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Controlling Threats to External Validity
Selecting from larger populationParticipants
Treatments
Situations
Ecological validity-emulates the real world.*
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Types of Designs:
Pre-experimental Designs (invalid)One-shot studies
TO
One-group pretest-posttest
O1TO2Statistical analysis? Dt
Static group comparison (one shot w/2 groups)
TO1
---------------Statistical analysis? It
O2
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Types of Designs:
True Experimental DesignsRandomized-groups design
RTO1Statistical analysis? It
RO2
Extending the levelsrandomized-groups design
RT1O1Statistical analysis? Ab
RT2O2
RO3
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Types of Designs:
True Experimental Designs, contd-1 interaction
-2 main effects
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Types of Designs:
True Experimental Designs, contdA factorial design with a categorical factor (B)
RA1O1
B1RA2O2
RA3O3Statistical analysis? M
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RA1O4
B2RA2O5
RA3O6
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Types of Designs:
True Experimental DesignsPretest-posttest randomized-groups
RO1TO2
RO3 O4Statistical analysis? MFA
Extending the design on the RM factor
RO1TO2 TO3 Statistical analysis? MFA-RM
RO4O5O6
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Types of Designs:
True Experimental Designs, contdExtending the pretest-posttest randomized groups design on both factors
RO1T1O2T1O3
RO4T2O5T2O6
RO7O8O9
Statistical analysis? AN (covariate)
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Quasi-Experimental Designs:
Time Series (slope)D.T. Campbell and J.C. Stanley, Experimental and quasi-experimental designs for research.
Copyright 1963 by Houghton Mifflin Company. Reprinted with permission. -
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Quasi-Experimental Designs:
Reversal (return to baseline) -
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Quasi-Experimental Designs:
Ex Post Facto (discriminate)This is one of the pre-experimental designs, but with the treatment not under the control of the experimenter.
TO1
------------------Statistical analysis? A
O2
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Quasi-Experimental Designs:
Single ParticipantIdentify participant and follow over time.
Does the treatment produce the same effect each time?Are treatment effects cumulative, or does participant return to baseline?Does participants response become less variable over treatment times? -
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Quasi-Experimental Designs:
Is participants magnitude of response sensitive to multiple treatment applications?Do varying intensities, frequencies, and lengths of treatment produce varying responses?
Single Participant, contd -
Next Class
Chapter 15Abstracts tonightResearch Q?List of 10 references3 intro paragraphsRationale
Lit summary
Show the missing brick, purpose and hypotheses
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