Reserve retraction for fraud and major error

Today we are retracting a study that seemed to show that the outcome of pregnancy in diabetic women in northeast England was worse than that of diabetic women in Norway.1^–3 The authors have realised that they made a fundamental mistake.2 Data collected in Norway were meant to exclude codes for gestational diabetes but didn't.2 The conclusions cannot be allowed to stand, and a subsequent analysis shows no significant difference in outcome between women in the two countries known to have diabetes before pregnancy.2 Studies are most commonly retracted because of fraud, but there is no question of misconduct in this case. It was a simple mistake, and as soon as the authors realised it they asked us to retract the study.2 But when should editors retract studies?

Retraction is topical following two recent high profile cases.Nature Medicine has just retracted a German study that described how three patients with metastatic kidney cancer responded to a vaccine produced by fusing their tumour cells with immune cells.45^w1 An ombudsman's committee from Göttingen University conducted an inquiry. It did not find scientific misconduct but did find negligence in the documentation of the trial and preparation of the manuscript. Some of the 17 authors needed convincing that the study should be retracted.

The second retraction concerns a study inScience that showed that …