There are both ethical and scientific reasons for registering trials. People who participate in clinical trials expect their contributions to be made use of in improving health care for everyone. Open access to information about ongoing and completed trials will satisfy the ethical duty to trial participants and will promote greater trust and public confidence in clinical research. Clinical trial registration in open access registries will also reduce selective publication of trial results, because by registering a trial the researchers commit to report the findings in accordance with basic ethical principles.

Selective reporting, regardless of the reason for it, leads to an incomplete view of the trial and its results. In addition to the above, clinical trial registration will decrease wasteful duplication of research, promote international research collaboration and ensure more efficient and effective allocation of research funds