Assignment task: Incidence trends in head and neck cancers and human papillomavirus (HPV)-associated oropharyngeal cancer in Canada, 1992-2009 Tonia Forte • Jin Niu • Gina A. Lockwood • Heather E. Bryant
What hypothesis is addressed in the study?
Was the hypothesis well articulated by the authors?
What is the refutable prediction of the hypothesis?
What is the design of the study?
Is this an appropriate design for attempting to refute the prediction?
What are the independent "exposure" and outcome variables in the study?
How do results of the study influence your view of the hypothesis?
Consider now the likely induction period implied by the hypothesis; how would this influence research aimed at understanding causes of oropharyngeal cancer?
Are changes in the age composition of the Canadian population likely to explain the trends reported by the authors? Why or why not?
Does it seem plausible that the results could be explained by random or systematic bias, rather than the hypothesized mechanism? Explain why or why not, addressing individually each form of bias enumerated in the Study Critique Outline.