There is a discrepancy between the outcome of a meta-analysis published in 1997 of 89 trials of homeopathy by Linde et al and an analysis of 110 trials by Shang et al published in 2005, these reached opposite conclusions. Important data were not mentioned in Shang et al’s paper, but only provided subsequently
A review of data provided after publication of Shang et al’s analysis did not support the conclusion that homeopathy is a placebo effect. There was intermingling of comparison of quality and comparison of effects, and thus matching was lost. The comparison of effects was also flawed by subjective choices and heterogeneity.
The result in the subgroup from which the conclusion was drawn was further influenced by the choice of cut-off value for ‘larger’ trials. If we confine ourselves to the predefined hypotheses and the part of this analysis that is consistent with the comparative design, the only legitimate conclusion is that quality of homeopathy trials is better than of conventional trials, for all trials (p = 0.03) as well as for smaller trials with n < 100 (p = 0.003).