Cohort Studies

Cohort studies observe large groups of individuals and record their exposure to certain risk factors to find clues as to the possible causes of disease.
They can be prospective studies that gather data going forward, or retrospective cohort studies, which look at data already collected. This type of research can also help identify social factors that influence health.

This type of study design where one or more people (known as cohorts) are followed and subsequent status evaluations with respect to a disease or outcome are conducted to determine which participants exposure characteristics (risk factors) are associated. As the study is conducted, outcome from participants in each cohort is measured and relationships with specific characteristics determined.

Fundamentals of a cohort study:

  • Assemble cohorts of exposed and unexposed individuals
  • Compare the risks of incident outcomes in each cohort
  • Follow cohorts for the development of incident outcomes
  • Identify people who are free of disease at the beginning of the study


  • Cheaper & easier than a randomized controlled trial (RCT)
  • Subjects can be matched, which limits the influence of variables
  • The standardization of criteria/outcome is possible


  • Blinding/Masking is difficult
  • Cohorts can be difficult to identify from confounding variables
  • No randomization, which means that imbalances could exist
  • Outcome of interest can take a long time

For Answers to any questions you may have please call Dr. Jimenez at 915-850-0900