6070Reliability Validity

8/13/2019 6070Reliability Validity

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RELIABILITY & VALIDITY(with Tony Little)

This is a joke.


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RELIABILITY

Reliability deals with the consistency of measurement

in research.

Reliability is the quality that guarantees us that we will

get similar results when conducting the same test onthe same population every time.

Consider this ruler…


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RELIABILITY

Now compare this ruler…

With this one…


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RELIABILITY

Each ruler will give the same answer each time…

But this one will be wrong each time…


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RELIABILITY

Each ruler is reliable…

But reliability doesn‘t mean much when it is wrong…


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RELIABILITY

So, not only do we require reliability…

We also need…


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VALIDITY

Good Ruler

Bad Ruler


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VALIDITY

Validity deals with theaccuracy of the measurement


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VALIDITY

Internal Validity questions if we are measuring what

we think we are measuring.

I am trying to determine if my Capstone students are learning

the value of service to the community, so I give a survey at

the end of the semester asking if they think will continue

community service after they graduate. They all say they will.

Whaddaya think?

I want to know if research students “fudge” data to make

sure there research findings turn out the way the want them

to. So I ask each person if they tampered with the data and

they all said, “no.” Valid test?


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VALIDITY

External Validity questions questions if we can

generalize our results to a larger population.

I find that students at Belmont have a higher average score in

math than those in the University of Southern Indiana. Do

you think we could improve USI’s math scores by having

Belmont’s professors teach them? If Italians tend to have a lower incidence of heart attacks

than Americans, would we expect Americans to decrease

their heart attacks if they followed an Italian diet.


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VALIDITY

Internal Validity: are we testing what we think we are.

External Validity: can generalize our results to a larger

or different population. There are other types of validity that focus on specific

concerns researchers have concerning possible errors

of accuracy in their studies. The subject teeters on the

edge of philosophical debate about just how large a

threat these other concerns are. It is important, but

subject for more in-depth study.


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RELIABILITY AND VALIDITY

The Bottom Line:

We need both reliability and validity in research toinsure that we have consistent, accurate answers to

our research questions.

Research must reflect reality and without reliable,valid data (which is interpreted correctly and

consistently) research is meaningless.


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VALIDITY RELIABILITY

The End

(Still just a joke…)

6070Reliability Validity

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