Author defends meta-analysis that was criticised

BMJ 1999;319:256 ( 24 July )

Letters

Author defends meta-analysis that was criticised

The first 150 words of the full text of this article appear below.

EDITOR $---$ In their continuous and compelling search for faults in published research, Davey Smith and Egger have written a letterabout meta-analysis that is inaccurate.¹ In their referenceto a meta-analysis of observational data that I and colleaguesdid² and the reanalysis that followed³ the authors committwo sins. The first is to misquote the original paper and thesecond, more important, is not to cross check thefacts.

They say that "Cappuccio et al argued that this [their finding] could be expected." Nowhere in the original manuscript isthere such a statement. This interpretation has been carefullyconstrued from the paragraph discussing potential sources of heterogeneity,where we conclude that "it seems more likely that other characteristics,either not measured or not considered in the analysis, may explainthe differences across studies."² "Correcting the meta-analysisfor this error (and several other mistakes)," Davey Smith andEgger then plot . . . [Full text of this article]