A study that does not have statistically significant findings, indicating that the intervention being studied probably does not have a beneficial effect.
Note: This term can generate confusion because it refers both to statistical significance and the direction of effect (positive or negative). Since studies analyse multiple outcomes simultaneously, the criteria for classifying a study as “negative” are not always clear and, in the case of studies of risk or adverse effects, “negative” studies are ones that do not show a harmful effect.
Ant.: positive study.