We have recently become aware of two cases of publication of closely related data in papers submitted concurrently to Thorax and to another journal, without disclosure of the existence of the related paper. One of these concerns papers by Girault et al^1 2 and relates to a study of two forms of assisted ventilation in which the data published in Thorax¹ represent part of a study also published in Chest.² In the review process of the Thorax paper, which dealt with characteristics of assist control ventilation in patients with COPD, the associate editor and external reviewers all commented on the fact that data comparing assist control ventilation with pressure support ventilation would enhance the paper, and this comment was forwarded with other feedback to the authors. The authors duly responded with a revised manuscript which did not include pressure support ventilation data, and did not disclose either in the manuscript . . . [Full text of this article]