Introduction: Although those who conduct systematic reviews are adept at identifying weakness in trials and have been successful in promoting more rigorous research design they have been surprisingly blasé about shoddy reporting practices such as redundant publication.

Objective: To expose and denounce a nonobvious form of redundant publication that occurs when researchers from one or more centre(s) participating in a multicentre trial publish their results before the complete trial is reported.

Methods: A case study of two multicentre trials done on the new antipsychotic agent, risperidone.

Results: Over a dozen publications or reports describing these two trials in part and in full were found, often with no reference to the larger study and with different authors noted for each version.

Discussion: This form of redundant publication that we have dubbed 'disaggregation' is a breach of trust implicit to scientific publishing and can result in inadvertent double-counting of data and an overestimation of the consistency of research results. Denouncing practices such as disaggregation is not simply encouraging 'publication etiquette' - it is the promotion of ethical, inclusive and transparent research. Researchers, reviewers, editors and an informed readership all have a role to play in preventing the scientific literature from being used as a covert form of advertising.