Biostatistics And Epidemiology 3

Front 1

external validity

Back 1

the ability to generalize the study results.
also called extrapolation.

Front 2

internal validity

Back 2

the ability to reach the correct conclusion for those actually studied.
the extent to which the results of a study can be attributed to the interventions employed rather than to flaws in the research design.

Front 3

performance bias

Back 3

care provided to one group differs from that provided to another

Front 4

selection bias

Back 4

groups of exposed and unexposed subjects differ systematically in a way which affects the outcome.

Front 5

recall bias

Back 5

one group may be more likely to recall certain events.

Front 6

hindsight bias

Back 6

knowledge that an event has occurred leads to an inflated estimate of the true probability of that event.

Front 7

Hawthorn effect

Back 7

Observation Bias
subjects may behave differently when they know they are being observed.

Front 8

ecological fallacy

Back 8

erroneous inference that population level association holds true at the individual level.

Front 9

cross-sectional study

Back 9

the relationship between an exposure and an outcome is compared in a defined population at one point in time.

Front 10

case-control study

Back 10

persons with a particular outcome (cases) are compared to similar persons without outcome (controls) with respect to past exposures.
select on the basis of outcome (good for rare diseases.)
inherently retrospective (looking backward for risk factors).

Front 11

cohort study

Back 11

a group of persons with a particular exposure and a similar group without the exposure are followed in time and compared regarding the occurrence of an outcome(s) of interest.
select on the basis of exposure (good for rare exposures).

Front 12

descriptive study

Back 12

designed only to describe the distribution of variables without regard to causal or other hypotheses.
hypothesis generating.
no control group.

Front 13

analytic study

Back 13

designed to examine associations, hypothesized causal relationships.
has control group.