within-subjects factor
the independent variable under study in a within-subjects analysis of variance. This variable has multiple levels to which each participant is exposed. For example, if a researcher is interested in job performance differences as a function of work shift length (e.g., 8 hours, 12 hours, 24 hours) and has each participant work each shift length during the study, then work shift length is a within-subjects factor. Also called within-subjects variable.