In this issue, Karipidis and colleagues report the interesting finding of a possible association between non-Hodgkin lymphoma and occupational exposure to power-frequency magnetic fields.¹ Their results are important given that existing studies on this topic are few, with conflicting results.^2,3 As in any other community-based case–control study their subjects have been exposed to a variety of chemical and physical agents. The authors, like many others, have published associations between various occupational exposures and non-Hodgkin lymphoma in separate papers.^4–6 Every researcher ever involved in large and expensive community-based case–control studies focusing on an adverse outcome and occupational exposures will be aware of the factors increasing the likelihood of publication of the results of positive and negative exposure–response relations in multiple papers. These include a general trend towards shorter papers in journals, but an expectation that assessment methods are specifically tailored to the exposure in question and that other aspects of …