Most evidence-rating schemes recognize that the strongest evidence
accumulates from scientific evidence, also referred to as research.
Within the broad realm of research, studies vary in terms of the level,
quality, and strength of evidence they provide. The level of evidence is
determined by the type of research design; the quality of evidence is
determined by critical appraisal of study methods for validity and reli-
ability; and the strength of evidence is determined through synthesis
of the level and quality of evidence. Practice recommendations based
on sound scientific evidence have a greater likelihood of positively im-
pacting patient outcomes (Melnyk & Newhouse, 2014).
This chapter provides:
■■ An overview of the various types of research evidence
■■ Information on appraising the strength and quality of re-
search evidence
■■ Tips for reading research evidence