Sir

Your recent Editorial (Nature 439, 117–118; 2006) bemoans the recurring subject of ethics and fraud in scientific research. I contend that many journals contribute to the prevalence of bad science, because, when the fundamental observation that led to the original publication cannot be reproduced, it is nearly impossible to publish a paper documenting this. Hence, controversies persist in the literature over many years, simply because the corrected story either is never published, or is not published as prominently as the initial paper.

True, there is an extensive specialist literature where ambiguous or conflicting results can be addressed in detail, but the readership is limited. Some journals, such as Nature, have mechanisms for publishing technical comments on published research (Brief Communications Arising: online only; see http://www.nature.com/nature/authors/gta/briefcomms.html#a2), but these are few in number and must adhere to strict criteria.

Reviewers of contradictory results often ask that the authors explain how the original authors could have obtained their results. To quote a recent rejection letter, “an adequate explanation for the apparent contradictory findings is not provided”. Certainly, speculative explanations can be offered for some kinds of experimental differences. But it is never possible to prove how another lab obtained data that cannot be reproduced. One can only be certain of one's own data. This demand for explanation creates serious problems in the case of scientific fraud. In a minor case, the original authors may have fudged one small set of data to ‘prove’ their theory. In a more serious case, fundamental observations cannot be reproduced. Whether this irreproducibility is due to outright fraud, scientific incompetence or some combination cannot be determined by the authors who try to reproduce the result and fail.

Another often-made request of reviewers is that the original experiments be reproduced exactly. This sounds reasonable but, in fact, can become an absurd burden. Even if the methods section were complete and accurate, one can never say with certainty that one has reproduced the experimental conditions precisely. Instead, the appropriate approach is to design experiments to test the conclusions of the original paper. If these conclusions are disproved, then the details of how they were arrived at are not relevant.

Of course, a contradictory paper should be held to a higher standard than was the paper it refutes. But all journals must endeavour to correct errors, or those who perpetrate scientific misconduct (not necessarily outright fraud) will be rewarded, and those who try to correct wrong hypotheses in the proper hegelian manner — thesis, antithesis, synthesis — will be punished.