Examining test-retest reliability: an intra-class correlation approach.
BACKGROUND
There are limitations of inter-class correlation (usually, the Pearson's product-moment correlation) in evaluating reliability of an instrument. An intra-class correlation approach would be appropriate to examine the test-retest reliability of an instrument.


OBJECTIVE
To introduce an intra-class correlation approach to examine the test-retest reliability of an instrument.


METHODS
The method of constructing an intra-class correlation coefficient was presented.


RESULTS
The instrument with visual analog scales to measure the perceived competence to practice breast self-examination and perceived barriers to breast self-examination was tested. The intra-class correlation coefficient was 0.640.


CONCLUSIONS
The intra-class correlation is an alternative to test the reliability of an instrument and it is more sensitive to the detection of systematic error.
Yen
Miaofen
M
National Cheng Kung University, Tainan, Taiwan, ROC.
Lo
Li-Hua
LH
D016504:Breast Self-Examination; D005260:Female; D006801:Humans; D015399:Nursing Research / Q000706:statistics & numerical data*; D011594:Psychometrics / Q000706:statistics & numerical data*; D015203:Reproducibility of Results