POPH192 - Lecture 17 Flashcards
what is a descriptive study?
- look at a person, place, time
What is an analytical study?
- look at association and causation between exposures and outcomes
what are the two types of studies?
- observational
- interventional
what is observational study?
- passive
- collecting data made from observations
what is interventional study?
- active
- giving the participants a treatment or intervention
what is the gate frame?
Graphic Approach to Epidemiology
- contains PECOT
what is PECOT?
- Population
- Exposed group
- Comparison group
- Outcome
- Time
what types of study is cross sectional study?
- descriptive and observational
what do cross sectional studies measure?
measures exposure and/or outcomes at a single point in time
- date, event, during a specific period in time e.g. in the last 12 months
what are examples of cross sectional studies?
- survey
- the census
what does cross-sectional study calculate?
prevalence
- the proportion of a defined population who have a disease a a given point in time
how can we use the prevalence calculation to generate a hypothesis?
use the prevalence ratio
what can the findings of cross-sectional study be used for?
- we don’t know if the exposure or outcome came first as they were both assesed at the same time so the findings can only be used for hypothesis generation.
what are the strengths of cross sectional studies?
- assess multiple exposures and outcomes
- can be used to calculate prevalence, distribution of prevalence in population and hypothesis generation
- inexpensive and quick
what are the limitations of cross-sectional study?
- no temporal sequence (exposure and outcome measured at same time)
- can’t measure incidence or measures of association
- not good for rare exposures/outcomes
- not good for assessing transient/variable exposures or outcomes (temporary)
