Study Designs Flashcards
Define ‘experimental study’.
Used to study the effect of an intervention.
Define ‘control group’.
Group that is given a placebo or an
alternative intervention.
Define ‘experiment group’.
Group that is given the intervention being tested.
Define ‘randomised control trial (RCT)’.
A study in which a number of similar people are randomly assigned to 2 (or more) groups to test a specific drug, treatment or other intervention.
What is RCT useful for?
Studying causal effect of an intervention.
Define ‘observational study’.
Observe the effect of a risk factor (or a treatment) without changing who is/isn’t exposed to it (unlike experimental
studies).
- Individuals are observed in a natural status
Why is observational study less reliable than experimental study?
Causal inferences derived from observational studies are not as strong as those from experimental studies.
Define ‘prospective study design’.
Researchers will follow and observe a group of subjects over a period of time to gather information and record the development of outcomes.
List three features of prospective studies.
- Outcomes (even exposures) have not occurred when the study starts
- Sample includes people exposed or un-exposed to a risk factor
- Focus on the exposure groups
Define ‘retrospective study design’.
Uses existing data that have been recorded for reasons other than research.
List four features of retrospective studies.
- Outcomes of interest have already occurred when the study starts.
- Sample includes both cases & non-cases
- Focus on the outcome groups
- Data on exposures are from records or
participants’ recall.
Define ‘longitudinal study design’.
Researchers repeatedly examine the same individuals to detect any changes that might occur over a period of time.
List three features of longitudinal studies.
- Data on both exposures & outcomes are collected repeatedly, at multiple time points.
- Can assess both between- and within-individual variations
- Can study changes of a measure with age
Give two examples of longitudinal study.
- Height growth in childhood
- Decline of physical function over age
Why is longitudinal study an important study design in life course research?
It’s suitable for studying temporal effect.