Abstract
This article reviews the advantages and disadvantages of the experimental vis-a-vis the nonexperimental (observational) epidemiologic approach in the assessment of causal relationships. Nonexperimental epidemiologic strategies, including the study of ecologic correlations, concurrent and nonconcurrent prospective designs, as well as case-control and cross-sectional designs, are briefly discussed. Among the case-control designs, reference is made to matched and to “nested” case-control studies. These different design approaches are discussed in relation to issues of external validity, bias, confounding, interaction, and precision.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
