Cohort study design, Experimental study design, and Casual inference Flashcards
Group of people who share a common experience during defined time period.
Cohort
Group or groups of persons are defined on the basis of presence or absence of exposure to a suspected risk factor of a disease.
Cohort study
Investigator starts with group of individuals apparently free from the disease of interest.
Cohort study
Proceeds from a suspected cause or etiological agent to the disease outcome.
General feature of cohort studies
Follow-up studies, incidence studies, prospective studies, longitudinal studies, panel studies.
Cohort studies
[2] Time relationship between initiation of study.
- Conceptual sense
- Temporal sense
[2] Occuerrence of disease
- Prospective
- Retrospective
Factor that plays an essential role in producing an outcome.
Cause
Identifiable relationship between exposure and disease.
[association/cause]
Association
Presence of mechanism that leads from exposure to disease.
[association/cause]
Cause
Alteration in the frequency or quality of one event is followed by a change in the other.
[causal/non-causal]
Causal
Association is a result of the relationship of both factor and disease with a third variable.
[causal/non-causal]
Non-causal
Validity within the study.
[validity]
Internal validity
Estimate of effect measure is accurate.
[validity]
Internal validity
Not due to systematic error.
[validity]
Internal validity
Validity beyond the study.
[validity]
External validity
Estimate generalizable to bigger population.
[validity]
External validity
Not due to random error.
[validity]
External validity
Non-representative sample.
[bias]
Selection bias
Inaccurate information.
[bias]
Information bias
Mixing the effect of the exposure on the disease with that of a 3rd factor.
Confounding
Obtain overall estimate of the association (crude: crude RR).
Assessing confounding
[2] Methods to control confounding
- Design stage
- Analysis stage
Those who are positive on the first test will be subjected to the second test.
[sequential/simultaneous]
Sequential
Participants are subjected to two or more tests at the same time.
[sequential/simultaneous]
Simultaneous
Subject is disease (+) when tested (+) in both tests.
Net sensitivity
Subject is disease (-) when tested (-) in either test.
Net specificity
