Common Errors in Statistics (and How to Avoid Them), 4th Edition

THE AUTHORS

Begin your appraisal with the authors’ affiliations: Who conducted this study? What is their personal history conducting other studies? What personal interest might they have in the outcome?

Who funded the study? What is the funding agency’s history regarding other studies, and what is their interest in the outcome?

Henschke et al. [2006] reported that screening via computerized tomography increased the chances of early detection of lung cancer. The authors reported, correctly, that their research had been funded by 32 different entities, one of which was the Foundation for Lung Cancer: Early Detection, Prevention, and Treatment. They did not divulge that this foundation was headed by the principal investigator of the 2006 study, that it was housed at her academic institution, and that the only contributor during most of its existence was the Vector Group, the parent company of Liggett, a major tobacco company, that could have an interest in the study results.

Another excellent example is the report of Marshall et al. [2011] on medically supervised injecting facilities and the subsequent rebuttal by Pike et al. [2011]. The authors of the former reference are employed by government health agencies and academic institutions. The authors of the latter, a report that was not peer reviewed, are employees of institutes dedicated to promoting “traditional values,” opposing the legalization of drugs.