Module 12 Flashcards
Ecological Fallacy
The error of attributing the characteristics of a group to an individual
The ecological fallacy occurs when we ascribe to members of a group some characteristic they do not possess as individuals
Reverse Causation
Occurs when you believe an exposure causes an outcome, but the outcome causes the exposure.
This is a concern in cross-sectional studies because the temporal order of association between the exposure and the outcome can typically not be established.
What is the main objective of case reports or case studies
to document a comprehensive, detailed description of the cases under observation
What are the major drawbacks of case studies
The lack a comparison group
Generalizability (external validity) is limited because o the potential for biased selection of cases
Any association is prone to potential confounding
What is the primary value of an ecological study
They suggest avenues of research that may be promising in casing light on etiological relationships - they provide a setting that can be considered as hypothesis-generating
Why is reverse causality a potential issue in cross-sectional studies?
Because we do not know whether the exposure or outcome came first since they are assessed at the same point in time.
When is an ecological study advantageous?
Ecological studies are advantageous when individual-level data aren’t available. They are also good to use as a preliminary study to assess associations before conducting a more rigorous study. Lastly, ecological studies tend to be quick and cheap, which is a major advantage.
What is the biggest limitation of a cross-sectional study?
The temporal order of associations between exposures and outcomes cannot be established, which is necessary to infer causality.
What are the main advantages of cross-sectional studies?
Cross-sectional studies are typically quicker and easier to conduct and cost less money, and many exposures and outcomes can be assessed.
what is a cross-sectional study
Used to measure health outcomes and exposures at a point in time. They are good for:
Measuring prevalence (point prevalence)
Describe demographic characteristics
Understand the conditions in which an outcome occurs
And the exposures that are near the outcome
What are cross sectional studies good for
Relatively quick and easy
Can study multiple diseases and exposures
Help to estimate the burden of disease
Determine the priority of diseases in pop
It can be at one point or several points (serial ) to get to a trend
What are cross-sectional studies not good for
Cannot determine temporality
Often use convenient samples because of availability (non-random)
Not useful for rare diseases because they look at an entire population
Considered less reliable than cohort and case-control; generally viewed as hypothesis-generating
How to measure data
Odds ratio to measure
