Significant numbers of physicists believe colleagues get an undeserved share of the credit for academic research publications, according to a survey.
Two-thirds of scientists whose latest journal article had three or more co-authors told researchers that at least one had not made sufficient contribution to merit a mention according to one of the strictest sets of guidelines available, issued by the international committee of medical journal editors.
Even by the less exacting standards of the American Physical Society (APS), the world's largest physics organisation, almost a quarter still felt their last paper carried inappropriate credits.
Yet just 3 per cent said they had personally rejected an undeserving scientist who had expected to be included.
Co-authorship is a contentious issue that is coming under scrutiny as many assessments of research output rely at least in part on measuring publications and citations.
Eugen Tarlow, director of consulting at Avalon Business Systems and a member of the Council of Science Editors, analysed questionnaires returned by 3,537 members of the APS.
His findings, published in the British journal Science and Engineering Ethics this week, revealed widespread suspicion of inappropriate co-authors, though the level varied greatly according to which set of guidelines were applied.
Nevertheless, Dr Tarlow said that many physicists were hostile to his work and felt there was not a problem in crediting colleagues.
"Appropriate authorship assignment is one of the most sensitive issues in science. I think there are very strong social pressures - physics is very political," he said.
He said it was strange that physicists who were precise in their descriptions of the reality of a physical system did not exercise the same standards when describing their professional collaborations.
The study showed that 46 per cent of the respondents said the most important contributor on their last paper could not be identified by looking at the authorship list.
The results were dismissed by Alun Jones, chief executive of the Institute of Physics. He said he had not come across the problem during his time working on both sides of the Atlantic and was confident it was not a consideration in the UK.
"I'm rather surprised that the study's deductions have been based on the last paper published by the author because in science the contribution of an individual and group is based on a series of papers," Professor Jones said.