The value of RCT evidence depends on the quality of statistical analysis.

The authors examined statistical practices in 193 randomized controlled trials (RCTs) of psychological therapies published in prominent psychology and psychiatry journals during 1999-2003. Statistical significance tests were used in 99% of RCTs, 84% discussed clinical significance, but only 46% considered-even minimally-statistical power, 31% interpreted effect size and only 2% interpreted confidence intervals. In a second study, 42 respondents to an email survey of the authors of RCTs analyzed in the first study indicated they consider it very important to know the magnitude and clinical importance of the effect, in addition to whether a treatment effect exists. The present authors conclude that published RCTs focus on statistical significance tests ("Is there an effect or difference?"), and neglect other important questions: "How large is the effect?" and "Is the effect clinically important?" They advocate improved statistical reporting of RCTs especially by reporting and interpreting clinical significance, effect sizes and confidence intervals.

Comparison of face-to-face and internet interventions for body image and eating problems in adult women: an RCT.

OBJECTIVE: The aim of this study was to compare the outcomes following an eight-session, small group, therapist-led, intervention for body dissatisfaction, and disordered eating in adult women, delivered either in face-to-face or synchronous, internet mode. METHOD: Community women with high body dissatisfaction and internet access were randomly assigned to either face-to-face delivery (N = 42), internet delivery (N = 37), or delayed treatment control (N = 37). All groups were assessed at baseline and 8-9 weeks later. The intervention groups were reassessed at 6-months follow-up. RESULTS: Both intervention groups showed large improvements in body dissatisfaction compared with the delayed treatment control and these improvements were maintained at follow-up. However, posttreatment improvements were greater in the face-to-face than internet intervention. CONCLUSION: In adult women, it is desirable to deliver the body image intervention in a face-to-face mode, but the internet mode is effective and has the potential to increase access to therapy.