Table 2

Scientific, ethical, and moral reasons to support prospective registration of CTs [WHO, (33)].

1. There is a need to ensure that decisions about health care are informed by all of the available evidence.*
2. It is difficult to make informed decisions if publication bias and selective reporting are present.*
3. The Declaration of Helsinki states that “every trial must be registered in a publicly accessible database before recruitment of the first subject.”
4. Improving awareness of similar or identical trials will make it possible for researchers and funding agencies to avoid unnecessary duplication.*
5. Describing clinical trials in progress can make it easier to identify gaps in clinical trials research.*
6. Making researchers and potential participants aware of recruiting trials may facilitate recruitment.*
7. Enabling researchers and health-care practitioners to identify trials in which they may have an interest could result in more effective collaboration among researchers. The type of collaboration may include prospective meta-analysis.*
8. Registries checking data as part of the registration process may lead to improvements in the quality of clinical trials by making it possible to identify potential problems (such as problematic randomization methods) early in the research process.

*Reasons applicable to OSs. This wording has been broadened in the 2013 revision of the Declaration of Helsinki (30): “Every research study involving human subjects must be registered in a publicly accessible database before recruitment of the first subject.”