Test-retest reliability is a measure of the reproducibility of the scale, that is, the ability to provide consistent scores over time in a stable population. In an experiment with multiple time points, the expectation is that the measurement tool chosen could consistently reproduce the same result providing all other variables remain the same. Tools which do provide such consistency are regarded as having high test re-test reliability, and therefore appropriate for use in longitudinal research. The reliability scores can be calculated by understanding the magnitude of the relationship between test statistics thus, the correlation coefficient (r) is calculated. A measure providing the same output at every time point would deliver a perfect linear correlation of r = 1.
How to cite: Test-Retest Reliability [online]. (2016). York; York Health Economics Consortium; 2016. https://yhec.co.uk/glossary/test-retest-reliability/