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What is VALIDITY? What is RELIABILITY?. Predictive Validity Discriminant Validity Internal Validity External Validity. Construct Validity Face Validity Concurrent Validity Content Validity. There are many kinds of “Validity”. Which does the researcher mean?
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Predictive Validity • Discriminant Validity • Internal Validity • External Validity • Construct Validity • Face Validity • Concurrent Validity • Content Validity There are many kinds of “Validity”. Which does the researcher mean? If any are used they really need to be defined.
Construct Validity This ensures that the study measures elements that the researcher claims to be measuring How Do You Ensure Construct Validity? First define the construct of interest. This may be difficult with characteristics that cannot be observed, like self-esteem Typical Problems Items in a measure reflect a construct different than the one identified. Conditions used to represent the causal variable do not accurately portray it
Face Validity Do the items or questions “look like” they will do what they are supposed to do. How Do You Ensure Construct Validity? Ask people, both experts and non-experts, to comment on the items or questions that the research wants to present. Problem Just looking valid does not ensure true validity
Concurrent validity If there is already a measure or test, then a new test maybe more efficient in some way, faster to administer or less costly. If this is the case, and the new test can be shown to produce results similar to the old test the new test has concurrent validity with the old test. How Do You Ensure Concurrent Validity? How do you ensure concurrent validity conduct parallel research with the old and new tests and only when results are similar will there be concurrent validity Problem Probably triple the work load initially developing a new test.
Predictive Validity If the test can be shown to be able to predict something about the respondent(s) not only when administered but also at some later time, then it would be said to have predictive validity. Discriminant Validity The test has the ability to discriminate between different individuals or groups. http://www.socialresearchmethods.net/kb/convdisc.php
Internal Validity The degree to which the study demonstrates that the treatment caused a change in the behaviour Problem Internal validity does not guarantee external validity. Internally valid studies are more likely to: a) Be replicated by the researcher b) Have its methodology adopted by others
External Validity The degree to which the results could be generalized to different participants, settings, and times How Do You Get External Validity? Repeat in different settings. More generalized findings the better theory, increases with sample size and diversity, increases with variations in methodology. Typical Problems Most research samples college students. Cross-cultural differences in treatment outcomes and reactions to stimuli. The degree of control required for experiments is rarely present in the real world
There are many kinds of “Validity” Which does the researcher mean? If any are used they really need to be defined
Reliability and Validity on Target Low Reliability High Reliability Reliable but Not Valid Could tap into any concepts or none Taps into the right concept almost all of the time Taps into the wrong concept
Here two “items” do not tap into the target area. Here all “items” do tap into the target area. The scale of items are “consistently” hitting the target area and the total scale has high INTERNAL RELIABITY or High Internal Consistency
The test is taken in year 1 and then in year 2. If the results are similar there is STABILITY and the TEST - RETEST RELIABILITY The test is taken in year 1 and then in year 2. If the results are not similar there is NO STABILITY and the TEST - RETEST RELIABILITY is questionable. Either the test-retest reliability is low or something has happened to change the responses
Moral of the story:If a researcher says they know something about VALIDITY and RELIABILITY, then make sure what they say is VALID and RELIABLE!!!
Second Moral of the story:If a researcher tells you nothing about VALIDITY and RELIABILITY,then we know nothing aboutVALIDITY and RELIABLITY!!!