validity and reliability
Split-half reliability
The degree of agreement when a test is split in half and the reliability of first half is compared to the second half; a measure of internal consistency of an instru¬ment.
Reliability
The degree to which a test consistently measures what it is intended to measure.
Predictive validity
The degree to which a test is able to predict future performance.
Construct validity
The degree to which a test measures an intended hypothetical abstract concept (non-observable behaviors or ideas).
Content validity
The degree to which an instrument measures an intended content area.
Validity
The degree to which an instrument measures what it is intended to measure.
Intrarater reliability
The degree to which one rater can obtain the same rating for a given variable on multiple measurement trials; an individual's consistency of rating.
Internal validity
The degree to which the observed differences on the dependent variable are the direct result of manipulation of the independent variable, and not some other vari¬able.
External validity
The degree to which the results are generalizable to individuals (general population) or environmental settings outside the experimental study.
Test-retest reliability
The degree to which the scores on a test are stable or consistent over time; a measure of instrument stability.
Concurrent validity
The degree to which the scores on one test are related to the scores on another criterion test with both tests being given at relatively similar times; usually involves comparison to the gold standard.
Interrater reliability
The degree to which two or more independent (raters can obtain the same rating for a given variable; the consistency of multiple raters.
Placebo effect
subjects respond to a sham treat¬ment with positive effects
Threats to Reliability
1. Errors of measurement
Experimenter bias
Expectations of the researcher; about the expected outcomes of the study influence the results of a study.
Failure to exert rigid control over subjects and conditions
Intervening variables interact with the dependent variable
Face validity
The assumption of validity based on the appearance of an instrument as a rea¬sonable measure of a variable; may be used for initial screening of a test instrument but psy-chometrically unsound.
selection bias
The researcher introduces systematic sampling error,
Sampling bias
The researcher introduces systematic sampling error,
Hawthorne effect
The subject's knowledge of par¬ticipation in an experiment influences the results of a study.
