Strengths and weaknesses of cohort studies
The strengths and weaknesses of cohort studies are summarised below. Click each heading to find out more.
- Multiple outcomes can be measured for any one exposure
- Can look at multiple exposures
- Demonstrate the direction of causality
- Can establish incidence (i.e. absolute risk) directly
- Easier and cheaper to do than a RCT
- You can look at detrimental exposures/interventions which cannot be assessed in an RCT
- Costly and time consuming
- Long periods of follow-up needed for outcomes that take time to develop
- Prone to bias due to loss to follow-up
- Knowledge of exposure status may bias classification of the outcome
- Being in the study may alter the participant’s behaviour
- Not good for the study of rare disease as large sample sizes needed