Presentation on theme: "RELIABILITY & VALIDITY"— Presentation transcript:
1 RELIABILITY & VALIDITY What is Reliability?How Can We Measure Reliability?What is Validity?What are the Types of Validity?
2 What is Reliability? Extent to which a measurement is consistent There is always measurement error when measuring variables.Larger measurement error means lower reliability.
3 Ways of Measuring Reliability Inter-rater ReliabilityTest-Retest ReliabilityAlternate Forms ReliabilitySplit-Half Reliability
4 What is Validity?Extent to which a method measures what it is claimed to measureReliability is a prerequisite for validity
5 Content ValidityExtent to which an instrument includes appropriate contentConsult experts about content of test
6 Construct ValidityExtent to which the appropriate construct is measuredLook for agreement with accepted measures of the same constructReview literature to determine appropriate variables that represent the construct
7 Criterion Validity Extent to which behaviors are accurately predicted Concurrent validity – present performancePredictive validity – future performanceUse correlational research to determine and improve ability to predict
8 External Validity Extent to which the results can be generalized Improve ecological validity – how well the method represents appropriate situations/settings
9 Internal ValidityExtent to which the results represent the relationship of interestEliminate or control confounding variables - extraneous variables that change systematically with a variable of interest