Study Design - Case-control study, Cross-sectional study, Cohort study, Prospective Cohort study, Retrospective Cohort study. Correlation vs. causation.
Correspondence to Dr Brent E Hagel, Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada; brent.hagel{at}albertahealthservices.ca Background ...