ABSTRACT
Repeatability is a measure of the consistency of a method and, as such, is the extent to which an instrument produces exactly the same result when it is used in the same subject on more than one occasion. Within-observer variation may arise from inconsistent measurement practices on the part of the observer, from equipment variation or from variations in the ways in which observers interpret results. A significant result from Levine’s test would indicate that the standard deviation around the mean differences is significantly lower in one group than the other, and therefore that the test is more repeatable in that group. The effects of these practices will result in a lower measurement error and a higher intraclass correlation coefficient value for the measurement tools used. The likelihood ratio is the probability of a patient having a positive diagnostic test result if they truly have the disease compared to the corresponding probability if they were disease-free.
