There is substantial evidence that poorly designed and reported research can mislead decision making in clinical care. This review investigates the methodological quality of Swedish trials of a wide array of psychological and social interventions.

The review includes 302 articles published in peer-reviewed journals during 1990–2014, which evaluated a psychological or social intervention; included a randomized or nonrandomized control group with a pre–post- or pre-follow-up design; and targeted individuals in order to prevent or rehabilitate from physical, psychological, or social problems. The results are based on the information reported in the articles.

Overall, methodological quality increased with time. However, more recent studies contained methodological deficits. For example, few had used blinded data collectors, reported power analyses, or searched for adverse events.

The results indicate a potential risk of biased results in both older and newer trials. Possible implications for practice and research are discussed.