Within-subjects statistics for one observation tend to be a baseline observations to which future observations of an outcome are compared. When trying to establish treatment effects, a baseline measure should be taken to establish where participants "are" before an intervention to better understand how much change or stability has occurred as a result of treatment or time. The correct statistical test is chosen based on the scale of measurement of the outcome.
The outcome represents numerical designations or categorical values that describe exposures, characteristics, phenomena, events, or group membership.
The outcome variable is measured using an ordered numerical continuum, such as a Likert scale.
The outcome variable is an actual number that provides both a measure of distance and magnitude due to having a "true zero."
