Research detail

1. UNDERSTANDING
RELIABILITY & VALIDITY
Research Methods Tutorial Slide-Set 3

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Consider the dart boards shown
below.

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The marks you see on the targets
were left by darts thrown at them.

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If the goal was to hit the “Bullseye”
with each dart…
Then the
results
were
consistent
but off-
target

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Then the
results
were both
consistent
and
accurate
If the goal was to hit the “Bullseye”
with each dart…

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Then the
results
were
neither
consistent
nor
accurate
If the goal was to hit the “Bullseye”
with each dart…

7. RELIABILITY AND VALIDITY
Reliability has to do with
consistency
Validity has to do with
accuracy
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8. Research Methods 8
If the goal was to hit the “Bullseye”
with each dart…
We have
reliability
but not
validity

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We have
both
reliability
and
validity
If the goal was to hit the “Bullseye”
with each dart…

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We have
neither
reliability
nor validity
If the goal was to hit the “Bullseye”
with each dart…

11. RELIABILITY AND VALIDITY
To have validity we must first have
reliability
 i.e. reliability is a prerequisite for
validity
Reliability is a necessary but not
sufficient condition for validity
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Reliability is a necessary but not
sufficient condition for validity
We can
have
reliability
without
having
validity

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We cannot
have
validity
without
first having
reliability
In order to be valid the
measurement must be reliable

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Without
reliability,
we cannot
have
validity
Reliability is a prerequisite for
validity

15. SUMMARY
To have validity we must have
reliability
 Reliability is a prerequisite for
validity.
Reliability is a necessary but not
sufficient condition for validity.
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Data collected:
Reliable but not Valid

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Data collected:
Reliable and Valid

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Data collected:
neither Reliable nor Valid

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Reliable
Not Valid
Reliable
Valid
Not Reliable
Not Valid
Conclusion

20. RELIABILITY AND VALIDITY
Reliability has to do with
consistency of measurement.
Validity has to do with accuracy of
measurement.
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21. THE END
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