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KNR 295Measureme
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Construct Validity
So construct validity assesses how well your procedures/measures match your ideas/theories General = construct Specific = operationalization
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Construct Validity
Two views – Definitionalist
“The construct,the whole construct, and nothing but the construct”
Impossible! Relativist
Define your construct Explain how and why what you’re doing
measures the construct in question Produce some evidence (whether we do this
depends on the kind of research in question)
US
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Construct Validity
Translation validity Face validity Content validity
Criterion-related validity Predictive validity Concurrent validity Convergent validity Discriminant validity
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Construct Validity
Translation validity vs. Criterion-related validity Translation validity assesses whether
the operationalization matches what you know of the construct
Criterion validity actually measures this assessment (uses other measures to assess the construct validity)
What we do is translation validity – arguing about the construct validity but not measuring it directly
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Construct Validity
Translation validity Face validity:
Does it look like you got it right? Ask others…more objective
Content validity Good definition of the construct Good match between your measure and
the definition E.G. Fitness program – does it abide by
ACSM guidelines?(e.g. construct…Body fat. Measure…sum of
skinfolds)
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Construct Validity
Criterion-related validity – all involve some direct test of CV Predictive validity
Does it predict what it ought to? E.G. Does sum of skinfolds predict
cardiovascular disease? Concurrent validity
Can your measure discriminate between 2 similar groups?
E.G. Measure sum of skinfolds of males and females – females should be higher than males(?)
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Construct Validity
Criterion-related validity Convergent validity
Correlation between this operationalization and other similar ones
E.G. Sum of skinfolds and…BMI, underwater weighing, cadaver dissection…
Discriminant validity This operationalization is different from other stuff
that is not supposed to measure the same thing E.G. Sum of skinfolds vs. age, vs. weight, vs.
gender, and so on. Note – this is why these items are included in
popular equations converting sum of skinfolds to BF%
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Construct validity
Convergent vs. Discriminant Validity Note – once you’ve done this, you still
need translation validity to establish that the measures are what you purport them to be
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Threats to Construct Validity
The laundry list… Use this to “ask the right questions” about the studies you critique
& so to begin…
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Threats to Construct Validity
Inadequate preoperational explication of constructs Construct not defined carefully
enough
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Threats to Construct Validity
Mono-operation bias (independent variable) Only one example of the construct E.G. only one training program…but
there are many out there Mono-method bias (dependent
variable) Only one example of the construct E.G. only one strength measure for a
program that trained the whole body
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Threats to Construct Validity
Interaction of different treatments Use one or more control groups to
isolate cause E.G. You want to show that strength
training improves self-esteem…but it could have been as a result of meeting you 3 times per week, not strength training…so use a control group to compare results
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Threats to Construct Validity
Interaction of testing and treatment Imagine I was interested in whether
research methods improved reasoning skills… If I tested you every week on some IQ
tests, these become part of the treatment, and impair construct validity (you might be getting better because of the test, not because of being in research methods)
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Threats to Construct Validity
Restricted generalizability across constructs “Unintended consequences” E.G. Finnish epidemiological study –
divide people into groups according to level of smoking & cholesterol
Take half of each group and assign to fitness & nutrition program, half untreated
All in fitness and nutrition program reduced smoking and improved fitness measures
BUT they also had increased all cause mortality!!! (may be an apocryphal story)
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Threats to Construct Validity
Confounding constructs and levels of constructs “I’m finding out whether aerobics or
strength training has the greater impact on muscle tone” Ok, but what amount of strength training?
How often are they doing aerobics? The labels are not in sufficient detail Could be that only the particular versions
of these programs that you used will produce the results you found
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Threats to Construct Validity
Social threats to construct validity Hypothesis guessing
I never collect data using people that have completed my motor learning class…
Evaluation apprehension Experimental booth in Bangor…
Experimenter expectancies I love my research…
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