Since a few years almost all scientific journals require pre-registration of clinical trials at offical trial registries. If trials are not registered, publication of the results is often not possible. At CAPHRI we recommend registering at one of the following trial registries:
Registration of observational research (hypothesis testing)
Considering the trustworthiness of observational research and the often described bias as a result of posthoc hypotheses and analyses, it is expected that soon pre-registration will also be a requirement for publication of all types of research. The above mentioned registries also offer the possibility to register observational research. For systematic reviews and meta-analyses there are specific registries such as The Cochrane Database (http://www.cochranelibrary.com/cochrane-database-of-systematic-reviews/index.html) and the Prospero Database (https://www.crd.york.ac.uk/PROSPERO/) .