Degree of Scientific Evidence
Meets CDC-designated "Best Evidence"
Intervention has been shown to be effective in a randomized controlled trial. The intervention was tested by comparison of two groups: an intervention group and a control group; participants were randomly assigned to either group. Random assignment increases the likelihood that the differences between the intervention group and control group can be detected. Without randomization, the effectiveness is less certain. Either there were no significant differences in baseline measures of outcome variables between the two groups, or the differences were controlled for in the analysis. There were at least 50 subjects in both groups at all data collection points, and at least 70% of subjects in each group participated in follow-up data collection. Follow-up data was collected a minimum of three months after the intervention ended in order to demonstrate sustainability of the intervention.
Evaluation shows that there was more than one significant increase in preventive behaviors or decrease in risky behaviors. There was also no significant reduction of preventive behaviors or increase toward risky behaviors.
CDC-designated "Promising Evidence"
Intervention has been shown to be effective in a randomized controlled trial. The intervention was tested by comparison of two groups: an intervention group and a control group; participants were randomly assigned to either group. Random assignment increases the likelihood that the differences between the intervention group and control group can be detected. Without randomization, the effectiveness is less certain. Either there were no significant differences in baseline measures of outcome variables between the two groups, or the differences were controlled for in the analysis. There were at least 50 subjects in both groups, and at least 60% of subjects in each group participated in follow-up data collection. Follow-up data was collected a minimum of one month after the intervention ended.
Evaluation shows that there was at least one significant increase in preventive behaviors or decrease in risky behaviors. There was also no significant reduction of preventive behaviors or increase toward risky behaviors.
Shows Promise
Intervention has been shown to be effective in preliminary implementation studies, but has not been evaluated utilizing randomized controlled trial. The study used either a single group pre-post test or a non-randomized control group. If a pre-post design was used, data were collected from a single group at the beginning of the intervention and were compared to data collected from the same group at the end of the study. If there was a control group, there was no random assignment of subjects to either the intervention group or control group. The subjects were not objectively assigned to a group; there was reason for placement in a certain group. Random assignment increases the likelihood that the differences between the intervention group and control group can be detected. Without randomization, the effectiveness is less certain.
Evaluation shows that there was at least one significant increase in preventive behaviors or decrease in risky behaviors and no significant reduction of preventive behaviors or increase in risky behaviors.
The evaluation may have been limited by having less than fifty subjects in the intervention and/or comparison groups, or by having less than 60% of subjects participating in follow-up data collection. Additionally, the analysis may have been limited if follow-up data was collected less than one month after the intervention or if substantial data was missing.
Potentially Effective
Intervention may have initially appeared to be effective, but did not produce similar results when evaluated by randomized controlled trial. There was either no significant change toward preventive behaviors or evidence of a significant change toward risky behaviors. Modification of the intervention may be effective.
Research Ongoing
Intervention is based on scientific theory and is suitably designed. Intervention has undergone process evaluation and formative findings indicate that the intervention is appropriate for the population. However, effectiveness of the intervention has not yet been formally evaluated utilizing scientific methods.