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What’s so special about being evidence-based?

We’re proud that SOS Signs of Suicide is evidence-based. But what exactly do we mean by that and what does that say about SOS?

Our suicide prevention education program – at both the middle and high school levels – has been scientifically evaluated by professional researchers, who have applied the “gold standard” of research studies – randomized controlled trials. These studies were conducted to determine if SOS is succeeding at its stated goals: reducing suicide deaths and spreading awareness about depression and suicide among adolescents. Randomized controlled trials (RCTs) involve splitting study participants into multiple groups by chance. One of these groups is the “control” group, which receives no intervention (in our case, this group would be students who will not participate in SOS until the RCT is completed). Another is the “treatment” group, which does receive the intervention (again, in our case, this would be students who will receive SOS student training). After the intervention, both control and treatment groups are surveyed or assessed on a range of predefined measures. Researchers can then use the information from the control group as a baseline to compare any differences in the information from the treatment group.

The first clinical trial evaluating SOS was published in 2004 with a follow-up and extension published in 2007. The results of this study demonstrated that youth who received SOS student training were approximately 40% less likely to report a suicide attempt in the three months after the training compared to youth who hadn’t been through the SOS program. Furthermore, exposure to the SOS curriculum resulted in greater knowledge of depression and suicide and more adaptive attitudes toward these problems.

“This [study] provides confirmation that the SOS program is a potent tool for curtailing suicidal behavior among diverse groups of high school-aged youth in the United States. SOS continues to be the only universal school-based suicide prevention program for which a reduction in self-reported suicide attempts has been documented with a randomized experimental design. As such it merits serious consideration from teachers, school counselors, and administrators seeking to bolster their school’s health curricula and prevention portfolio.” (Aseltine et al., 2007, “Evaluating the SOS suicide prevention program: a replication and extension”)


In 2016, another study was published, which provided further evidence of SOS’s effectiveness. This RCT built on the previous study by adding another important element of program evaluation: pre- and post-testing – which means simply that members of each group were surveyed before and after the SOS program was administered. This trial found that students who received SOS training were approximately 64% less likely to report a suicide attempt in the three months after the training compared with students who hadn’t been through the SOS program.

“…[T]his study has strengthened and extended evidence that SOS prevents suicidal behavior, both planning and attempts, in vulnerable high school students, and has increased confidence for causal inference by including pre-test measures in the evaluation.” (Schilling et al., 2016, “The SOS Suicide Prevention Program: Further Evidence of Efficacy and Effectiveness”)


Finally, a third clinical trial published in 2014 specifically examined the SOS middle school program, where the previous studies had focused on the SOS high school program. Participation in SOS was associated with increases in knowledge of suicide and depression. Additionally, students who reported suicidal ideation in the pre-test before receiving SOS training were 96% less likely to report suicidal behaviors (ideation, planning, and/or attempts) at the post-test after participating in the SOS program than students with pre-test ideation in the control group.

For full details on all of these studies, check out our case study on the Evidence Behind SOS Signs of Suicide.