Define validity
- Is the degree of truthfulness of a test score
- The degree to which the test or instrument measures what it is supposed to measure
What two characteristics is validity dependent on
Relevance
Reliability
What are the two types of validity that are logical validity
Face validity
Content validity
Define face validity
- Infers that a test is valid by definition
- It is clear that the test measures what it is supposed to
Define content validity
- Infers that the test measures all aspects contributing to the variable of interest
- e.g. who is the most physically fit
Two types of validity that are statistical validity
concurrent validity
Predictive validity
Define concurrent validity
- Infer that the test produces similar results to a previously validated test e.g. VO2 max
Define predictive validity
- Infers that the test provides a valid reflection of future performance using a similar test, e.g. can performance during test A be used to predict future performance in test B
Validity type that is both logical and statistical
Construct
Define construct validity
- Infers not only that the test is measuring what is supposed to, but also that it is capable of detecting what should exist, theoretically
- Therefore relates to hypothetical constructs
Define reliability
- Reliability relates to the consistency or repeatability of an observation
- Degree to which repeated measures of the same trait are reproducible under the same conditions
Test reliability is sometimes discussed in terms of….
Observed score
true score
error score
Observed score equation
Observed score = true score + error score
Define internal consistency
Internal consistency reliability is a way to gauge how well a test or survey is actually measuring what you want it to measure.
What does test-rest measure
It reflects the variation in measurements taken by an
instrument on the same subject under the same conditions
Define kappa - interrater reliability
The consistency of a given measurement from categorical outcomes
Define Intraclass Correlation Coefficient (ICC)
s a descriptive statistic that can be used when quantitative measurements are made on units that are organized into groups. It describes how strongly units in the same group resemble each other.
Threats to internal validity
- Maturation
- History
- Statistical regression: An initial extreme score is likely to be followed by less extreme subsequent scores
- Instrumentation e.g. Uncalibrated equipment
- Selection Bias, e.g. Groups not randomly assigned
Threats to external validity
Hawthorne effect
Demand characteristics
Define hawthorne effect
subject is influenced by the fact that it is being recorded, e.g. Fastest sprint when professor enters lab
Define demand characteristics
Participants detect the purpose of the study and behave accordingly
Define internal validity
Internal validity is the extent to which a piece of evidence supports a claim about cause and effect
Define external validity
External validity is the validity of applying the conclusions of a scientific study outside the context of that study
