Brennan (2001) also acknowledged the difficulty of handling the facet of time, but from a
different perspective. He emphasized the importance of conceptualizing the replication of a mea-surement procedure that was the heart and soul of the concept of measurement reliability. If a test
taken on one occasion was considered the measurement procedure and a replication constituted
taking the same test on a different occasion, then variance of scores across the two occasions
would be an adequate estimate of random fluctuation across replications of the measurement
procedure. Data obtained from closer occasions would not likely be affected by changes in true
score, but data obtained from occasions that were too far apart might confound random error with
changes in true scores. Such confounding, if it happened, would not be easy to be unconfounded.
As Brennan stated: