Convergent and Discriminant Validity

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Convergent and Discriminant Validity
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The Convergent Principle

• measures of constructs that are related to each
  other should be strongly correlated

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How it works
Theory
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How it works
Theory
you theorize that the items all reflect self
esteem
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How it works
Theory
1.00 .83 .89 .91 .83 1.00 .85 .90 .89 .85 1.00
.86 .91 .90 .86 1.00
Observation
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How it works
Theory
1.00 .83 .89 .91 .83 1.00 .85 .90 .89 .85 1.00
.86 .91 .90 .86 1.00
the correlations provide evidence that the items
all converge on the same construct
Observation
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The Discriminant Principle

• measures of different constructs should not
  correlate highly with each other

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How it works
Theory
locus of control construct
LOC1
LOC2
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How it works
you theorize that you have two distinguishable
constructs
Theory
locus of control construct
LOC1
LOC2
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How it works
Theory
locus of control construct
LOC1
LOC2
rSE1, LOC1 .12
rSE1, LOC1 .09
rSE1, LOC1 .04
rSE1, LOC1 .11
Observation
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How it works
Theory
locus of control construct
LOC1
LOC2
rSE1, LOC1 .12
the correlations provide evidence that the items
on the two tests discriminate
rSE1, LOC1 .09
rSE1, LOC1 .04
rSE1, LOC1 .11
Observation
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Putting It All Together

• Convergent and Discriminant Validity

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we have two constructs we want to measure, self
esteem and locus of control
Theory
self esteem construct
locus of control construct
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we have two constructs we want to measure, self
esteem and locus of control
Theory
self esteem construct
locus of control construct
SE1
SE2
SE3
LOC1
LOC2
LOC3
for each construct we develop three scale items
our theory is that items within construct will
converge, across constructs will discriminate
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Theory
self esteem construct
locus of control construct
SE1
SE2
SE3
LOC1
LOC2
LOC3
Observation
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Theory
self esteem construct
locus of control construct
green and red correlations are convergent, blue
are discriminant
SE1
SE2
SE3
LOC1
LOC2
LOC3
Observation
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Theory
self esteem construct
locus of control construct
SE1
SE2
SE3
LOC1
LOC2
LOC3
the correlations support both convergence and
discrimination, and therefore construct validity
Observation
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