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The Survival of the Fittists

Understanding the role of replication in research is crucial for the interpretation of scientific advances

Howard Wainer

An Exception to the Rule

The stage is now set for us to shift our gaze to research done in the East. Chinese medical research, for example, is almost invisible to Western scientists, but the reverse is not true: Chinese researchers seem well aware of major findings in the West, although they are probably less familiar with the more minor publications. Keeping in mind the phenomenon of shrinking effect sizes, if we looked carefully at the findings of Chinese medical researchers as they strive to replicate Western medical findings, we would expect to find the same shrinkage as is the rule in the West. Is this what happens?

2012-09MacroWainerFC.jpgClick to Enlarge ImageZhenglun Pan, of Shandong Provincial Hospital in Shandong, China, and a team of international scholars did a large meta-analysis of dozens of studies done in China that were meant to be replications of earlier studies. They then redid the same meta-analysis with studies from other Asian (but non-Chinese) researchers, as well as non-Asian, non-Chinese researchers. The studies they considered, in the field of genetic epidemiology, seemed to find effect sizes at or surpassing those found in the alpha study. The authors call this a “reverse Tower of Babel” bias. Although the bias was greatest in Chinese studies, it was also found, to a lesser extent, in non-Chinese Asian research. Replication studies on the same subject by non-Chinese, non-Asian researchers found the smallest effect sizes of all. (Summaries of two of the meta-analyses by Pan and colleagues are shown on the facing page.) Several speculative reasons for this effect come to mind—perhaps it is a matter of cultural norms; perhaps there is an interaction between treatment and ethnicity. Thus far we must await further research to determine its sources.

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