'Publication bias need not lead to asymmetry in funnel plots.'
...that's not my opinion , it's a quotation from the Cochrane Handbook for Systematic Reviews of Interventions, which Cipriani et al say they have followed, and even provide the link to: http://handbook-5-1.cochrane.org/.
But they seem to have ignored this, and relied wholly on symmetry in their plots to rule out publication bias. See pp 179-81 of the Appendix.
They acknowledge that 'the field of antidepressant trials in the past has been prone to publication bias' (pp 237, 255), but given that pharmaceutical companies were their only significant source of non-registered trials, studies such as this appear to be an ideal way to circumvent the bias-preventing effects of independent registration.
Such companies are primarily answerable to their shareholders, not to patients. It is disappointing that the BMJ has reported that this publication 'ends doubts'.
Rapid Response:
'Publication bias need not lead to asymmetry in funnel plots.'
...that's not my opinion , it's a quotation from the Cochrane Handbook for Systematic Reviews of Interventions, which Cipriani et al say they have followed, and even provide the link to: http://handbook-5-1.cochrane.org/.
But they seem to have ignored this, and relied wholly on symmetry in their plots to rule out publication bias. See pp 179-81 of the Appendix.
They acknowledge that 'the field of antidepressant trials in the past has been prone to publication bias' (pp 237, 255), but given that pharmaceutical companies were their only significant source of non-registered trials, studies such as this appear to be an ideal way to circumvent the bias-preventing effects of independent registration.
Such companies are primarily answerable to their shareholders, not to patients. It is disappointing that the BMJ has reported that this publication 'ends doubts'.
Competing interests: No competing interests