The document discusses the concepts of reliability and validity in research methods. It states that reliability refers to consistency of measurement, while validity refers to accuracy of measurement. It also explains that reliability is a necessary prerequisite for validity - to have a valid measurement, it must first be a reliable measurement. This is illustrated using examples of dart throws hitting targets with varying levels of consistency and accuracy.

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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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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