conflict of interest

Papers end with a statement of the authors' relationships and activities, and readers often do not know what to do with it. The International Committee of Medical Journal Editors, whose recommendations most medical journals follow, defines a conflict of interest as occurring when professional judgment concerning a primary interest, such as patients' welfare or the validity of research, may be influenced by a secondary interest, such as financial gain. The definition turns on the possibility of influence rather than on proof of it, and the committee adds that perceptions of conflict of interest are as important as actual conflicts of interest.

What has to appear is set out rather than left to taste. Articles must declare the authors' relationships and activities; the sources of support for the work, including sponsor names along with explanations of the role of those sources; and whether the authors had access to the study data, with an explanation of the nature and extent of that access. The third requirement is the one most often passed over, and it is the one that separates a study a company merely paid for from a study a company also designed, ran or analysed.

The committee is equally clear about what a declaration does not settle. The presence of a relationship or activity does not always indicate a problematic influence on a paper's content, so a disclosed interest is not a finding of bias and not by itself a reason to set a result aside. Its purpose is to move the judgement to the reader: the recommendations say that readers must be able to make their own judgments regarding whether an author's relationships and activities are pertinent to a paper's content. A declaration is information about the conditions a result was produced under, to be weighed beside the study's design, its size and who funded it rather than in place of them.