Tang K-C, Choi B C K, Beaglehole R
Department of Chronic Diseases and Health Promotion, World Health Organization, Geneva, Switzerland.
J Epidemiol Community Health. 2008 Sep;62(9):832-4. doi: 10.1136/jech.2007.061366.
Grading of evidence of the effectiveness of health promotion interventions remains a priority to the practise of evidence-based health promotion. Several authors propose grading the strength of evidence based on a hierarchy: convincing, probable, possible and insufficient; or strong, moderate, limited and no evidence. Although these grading hierarchies provide simple and straightforward rankings, the terms that describe the categories in the hierarchies, however, do not explain, in an explicit manner, in what way the strength of the evidence in one category is more, or less, superior than that in another.
To enhance the explanatory power of the hierarchy, we propose that evidence be classified into three grades, each with a short explanatory note on the basis of three criteria: the degree of association between the intervention under study and the outcome factors, the consistency of the findings from different studies, and whether there is a known cause-effect mechanism for the intervention under study and the outcome factors.
For more in-depth grading, a three-grade expanded hierarchy is also recommended. Examples are given to illustrate our proposed grading schemes.
健康促进干预措施有效性的证据分级仍然是循证健康促进实践的重点。几位作者提议根据一个等级体系对证据强度进行分级：令人信服、很可能、有可能和不足；或者强、中、有限和无证据。虽然这些分级体系提供了简单直接的排名，但等级体系中描述类别的术语并没有明确解释一个类别中的证据强度比另一个类别中的证据强度更优或更劣的方式。
为了增强等级体系的解释力，我们建议将证据分为三个等级，每个等级都有基于三个标准的简短解释说明：所研究的干预措施与结果因素之间的关联程度、不同研究结果的一致性，以及所研究的干预措施与结果因素之间是否存在已知的因果机制。
为了进行更深入的分级，还推荐一个三级扩展等级体系。给出了示例来说明我们提议的分级方案。
