In a multiple baseline study, the “baseline” state of a patient is recorded before the experimental treatment is completed. Changes between the baseline and then the response to treatment are then evaluated. The baseline for the patient is then recorded again before another experimental treatment is completed. This allows the experimenter to account for change over time and change due to the first experimental treatment without it affecting the second treatment they are implementing.
Sackett 1996
Level of Evidence Study Design/Methodology of articles
I Systematic reviews, meta-analysis, randomized controlled trials
II Two groups, non-randomized studies (ex. cohort, case-control)
III One group, non-randomized (ex. before and after, pretest and post-test)
IV Descriptive studies that include analysis of outcomes (ex. single subject design, case series)
V Case reports and expert opinion, which include narrative literature reviews and consensus statements.