Examining the reliability of XXXX -Cog change scores.

@entity1 @entity73 @entity11509 @entity195
UNASSIGNED: The purpose of this study was to estimate and examine ways to improve the reliability of change scores on the @entity195 Assessment Scale, Cognitive Subtest ( @entity11509 -Cog). The sample, provided by the @entity195 Neuroimaging Initiative, included individuals with @entity195 ( @entity195 ) (n  =  153) and individuals with @entity73 ( @entity73 ) (n  =  352). All @entity1 were administered the @entity11509 -Cog at baseline and 1 year, and change scores were calculated as the difference in scores over the 1-year period. Three types of change score reliabilities were estimated using multivariate generalizability. Two methods to increase change score reliability were evaluated: reweighting the subtests of the scale and adding more subtests. Reliability of @entity11509 -Cog change scores over 1 year was low for both the @entity195 sample (ranging from .53 to .64) and the @entity73 sample (.39 to .61). Reweighting the change scores from the @entity195 sample improved reliability (.68 to .76), but lengthening provided no useful improvement for either sample. The @entity73 change scores had low reliability, even with reweighting and adding additional subtests. The @entity11509 -Cog scores had low reliability for measuring change. Researchers using the @entity11509 -Cog should estimate and report reliability for their use of the change scores. The @entity11509 -Cog change scores are not recommended for assessment of meaningful clinical change.
