Test-retest reliability assessment is used to establish that an instrument is capable of measuring a variable with consistency….If the test is reliable, the subject’s score should be similar on multiple trials. In terms of reliability theory, the extent to which the scores vary is interpreted as measurement error .
Test-retest reliability is the stability of a measuring instrument over time .
Test-retest reliability indicates stability of the assessment and determines the consistency of measures from one testing occasion to another, on the assumption that the behavior being scored does not change over time .
Reliability can be defined as the consistency of measurements, or of an individual’s performance, on a test; or “the absence of measurement error” .
Reproducibility evaluates whether an instrument yields the same results on repeated assessments. Examples of reproducibility are parallel-forms, rater and test-retest reproducibility .
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就我自己對test-retest reliability的概念，test-retest reliability可看二個方面，一個方面是重複施測結果的一致程度，另一方面是重複施測之測量誤差程度。
在FDT論文的test-retest reliability，我著重於重複施測結果的一致程度，而為要強調測量測量誤差，因為在此篇是著重於RCIp，列於practice effect底下，所以在test-retest reliability中，沒有刻意提到要看RCI。