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Chapter 20 Validity & Reliability - Coggle Diagram
Chapter 20 Validity & Reliability
A metaphor - "The target"
Neither reliable nor valid
Both reliable and valid
Valid not reliable
Reliable not valid
Validity & reliability are not separated issues in research but in fact, they are related to each other.
Validity is the degree to which an instruments measures what it intended to measure, and the degree to which the 'thing' that the instrument measures has meaning.
Reliability is how consistently a test measures what it attempts to measure.
Validity
Construct Validity - seek agreement between theoretical concept and a specific measuring device or procedure.
Content Validity - based on the extent to which a measurement reflects the specific intended domain of content.
Criterion Related Validity - Referred to instrumental validity which used to demonstrate the accuracy of a measure / produce by comparing it with another measure or procedure which has been demonstrated to be valid
Face validity - Concerned with how to measure or produce appears.
Self-report measures
Researchers can use control checks, such taking a question in several different ways, to increase the validity of self-report claims.
Much social science research relies on the reports, memories and experiences of human participants. Researchers need to know what people actually do or think, but this is difficult to ascertain.
Reliability
Test- Retest reliability - the agreement of measuring instruments over time. To determine stability, a measure or test is repeated on the same subjects as a future date.
Parallel-Forms / Alternate-Forms Reliability - Used to assess the consistency of the results of two similar types of test that are used to measure the same variable at the same time.
Inter-rater/Inter-observer Reliability - addresses the consistency of the implementation of a rating system. It is the extent to which two or more individuals agree.
Test for Homogeneity / Internal Reliability - the extent to which tests or procedures asses the same characteristics, skill or quality. It is the measure of the precision between the observers or of the measuring instrument used in a study
Difficulties of achieving reliability
Quixotic reliability - a single manner of observation consistently, yet erroneously, yields the same result.
Diachronic reliability - the stability of observation over time. This type of reliability is appropriate to asses features that remain relatively unchanged over time such as landscape benchmark, the same level reliability is more difficult to achieve with socio-cultural phenomena.
Synchronic reliability - refers to the similarity within the same time frame. It rarely involves observations of identical things but it concerns itself with particularities of interest to the research.
Validity is important because if an instrument does not accurately measure what it is supposed to, there is no reason to use it even if it measures.
Reliability is also important to measure the consistency of your measurement, or the degree to which an instruments measures the same way each time it is used under the same condition with the same subjects.