Test-Retest Reliability

Test-retest reliability is a statistical technique used to estimate components of measurement error by repeating the measurement process on the same subjects, under conditions as similar as possible, and comparing the observations. The term reliability in this context refers to the precision of the measurement (i.e. small variability in the observations that would be made on the same subject on different occasions) but is not concerned with the potential existence of bias.

In the context of surveys, test-retest is usually in the form of an interview-reinterview procedure, where the survey instrument is administered on multiple occasions (usually twice), and the responses on these occasions are compared.

Ideally the reinterview (henceforth referred to as T2) should exactly reproduce the conditions at the original interview (T1). Unfortunately, learning, recall ...