Table 1.

Measures to reduce publication bias

Research sponsors' guidelines	Guidelines such as the EU Clinical Trials Directive, the Declaration of Helsinki, and the CONSORT Statement have been developed so that researchers can follow the same sets of standards. Guidelines that stress the importance of reporting both positive and negative findings can help prevent selective reporting of outcomes.
Prospective trial registration and mandatory availability of trial results in registry	Prospective registration of trials and mandatory reporting of results within 2 years is required by US law. This is an attempt to prevent the “file-drawer” problem of unfavorable results disappearing. Even without regulation to enforce publication of results, trial registries increase transparency. Since 2005, the ICMJE have applied a policy of accepting only manuscripts of trials that have been prospectively registered, however, not all medical journal adhere to the ICMJE policy.
Right to publication	Ensuring that researchers, and not funders, have the proprietary right to publish results of research conducted in their clinics would reduce the “file-drawer” problem of unfavorable results never being published.
Peer review	Targets for changes to the publication process might include the peer review process, mandatory disclosure of conflict of interest, or electronic publication. Peer reviewers have been criticized for rejecting manuscripts with negative or null results and for being biased toward their own country or language and one measure that might reduce this bias is blinding of peer reviewers.
Disclosure of conflict of interest	Disclosure of conflict of interest enables readers to determine whether the authors of a trial manuscript may have motives to present the results in a more favorable light (and may increase the readers' suspicion of reporting biases).
Electronic publication	Because of their unlimited size, electronic journals could accept all methodologically sound manuscripts regardless of the direction of the results (reducing positive outcome-reporting bias).
Open-access policy	May mean open access to all trial results or the open-access publishing model—where authors pay a publishing fee and articles are freely available to all readers. The latter is a method to counteract the barrier of a “pay-wall” for users of the medical literature.

Abbreviations: CONSORT, Consolidated Standards of Reporting Trials; ICMJE, International Committee of Medical Journal Editors.