Longitudinal Studies and Determination of Risk

  • Sean W. MurphyEmail author
Part of the Methods in Molecular Biology™ book series (MIMB, volume 473)


Longitudinal and observational study designs are important methodologies to investigate potential associations that may not be amenable to RCTs. In many cases, they may be performed using existing data and are often cost-effective ways of addressing important questions. The major disadvantage of observational studies is the potential for bias. The absence of randomization means that one can never be certain that unknown confounders are present, and specific studies designs have their own inherent forms of bias. Careful study design may minimize bias. Establishing a casual association based on observational methods requires due consideration of the quality of the individual study and knowledge of its limitations.

Key words

Longitudinal studies cohort study case–control study bias risk factors sample size estimate 


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Copyright information

© Humana Press, a part of Springer Science+Business Media, LLC 2008

Authors and Affiliations

  1. 1.Health Sciences CentreNewfoundlandCanada

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