Expert Working Groups explicitly describe how they were able—or not—to rule out these sources of error with reasonable confidence, as seen in recent evaluations of night shift work,4 opium consumption5 and aniline.6 Many approaches to evaluating the direction and magnitude of biases in observational epidemiology have been described in the scientific literature—some new,7 and some existing for decades.8 To make these methodological developments more easily accessible to those conducting cancer hazard identification, the Monographs programme and the National Cancer Institute’s Division of Cancer Epidemiology and Genetics convened a scientific workshop of global experts in cancer epidemiology and in statistical and epidemiological methodology. ...attendees outlined approaches that researchers could adopt to assess the impacts of each source of bias in their own studies. The workshop materials will result in the publication of a new volume in the IARC Scientific Publications series Statistical Methods in Cancer Research, which includes the landmark publications on cohort and case–control studies authored by Breslow and Day.9 10 The new Scientific Publication, expected in early 2024, will summarise methods for bias assessment to support cancer hazard identification, illustrate these methods with examples and discuss how these methods could also be incorporated into future published studies to better inform cancer hazard and risk assessments. Funding This work was supported by the International Agency for Research on Cancer (IARC) and by the National Cancer Institute’s Intramural Research Program, Division of Cancer Epidemiology and Genetics.