How to Summarize Single-Participant Research: Ideas and Applications

Abstract

This article describes the need for systematic methods for summarizing single-participant research, describes various approaches for quantitative synthesis, and reviews conclusions of completed synthesis efforts. There is general, but not universal, agreement for the need for systematic literature-review procedures. Areas of disagreement center around the issue of whether outcomes of single-participant research studies can be represented by a single common metric and, if so, which metric is the most useful. Although several alternatives are reviewed, we recommend the use of the percentage of nonoverlapping data metric, and we describe several instances in which it has been employed effectively.