Term
| flow chart of epidemiologic studies |
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Definition
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Term
| how are individs selected for in case control studies |
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Definition
| study subjects are based on disease and outcomes status |
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Term
| how are exposures assigned in case control studies |
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Definition
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Term
| do case control studies measure prevalence or incidence? |
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Definition
| both. but more so prevalence. Incidence can be used if they are enrolled as they are diagnosed. |
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Term
| which is faster to conduct, prevalence or incidence? |
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Definition
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Term
| what are the four advantages for case control studies |
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Definition
good for rare diseases (but not for rare exposers)
best design for investigating source of outbreak
good for identifying multiple risk factors for a single disease
retrospective and therefore relatively fast and inexpensive |
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Term
| 5 disadvantages of case-control studies |
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Definition
control selection can be difficult
cannot measure disease incidence or prevalence
can only study one outcome
subject to many different types of bias (selection, information, confounding)
temporal issues if using prevalence |
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Term
| preventing false positives has what effect on the measure of association |
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Definition
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Term
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Definition
| population from which cases and controls are obtained |
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Term
| name and describe the two types of study bases |
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Definition
primary study base: population from which the cases arise clearly defined
secondary study base: one or more steps removed from a primary population. Population from which these cases arrive cannot be clearly defined. |
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Term
| give the advantage to primary population source and the advantage and disadvantage of secondary population source |
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Definition
primary population source: avoids potential selection bias
secondary population source: much cheaper and often more practical. conceptualizing source population and pikcing non cases for controls more difficult |
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Term
| define open population and closed population |
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Definition
open: has additions and withdrawals throughout study.
closed: no additions and few withdrawls throughout study. |
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Term
| how can you make an open population into a closed one? |
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Definition
| by shortening the timeframe of your study, thus creating a limited amount of time for movement of individuals to occur. |
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Term
| four prinicples for control selection in case-control studies |
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Definition
controls should come from same study base as cases
controls to be representative of the source population in terms of exposures and potential confounders
if using an open population or rate based selection, controls should mirror amount of exposure time of non-cases in population .
during time period, a noncase is eligable to be selected as a control, it should also be eligible to become a case if the disease occurred |
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Term
| describe how controls should be selected for a case control study for an open population and a closed population |
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Definition
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Term
| 3 rules for control selection for risk-based design |
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Definition
intended for closed population
select controls from sampling units in the popuatlion that did not become cases at the end of risk period
sampling unit can be selected as a control only once |
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Term
| what would happen if risk-based design was used in an open population for selecting controls |
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Definition
| would be significant bias because not all individuals may be avaiable to be selcted as controls at the time of risk sampling. |
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Term
| rate based selection for controls is intended for an open population. Is censoring of study subject, indenpendent, or not indpendent of exposure? |
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Definition
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Term
| what are the two options for rate based selection of controls |
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Definition
pick controls at defined or steady rate throughout the study period from risk set (non-cases eligible to become cases at that point)
pick a specified number of non-cases from the risks set when a case is enrolled (incidence denisty sampling ) |
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Term
| lis the four rules for rate based case-control studies for selecting controls |
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Definition
controls can become cases during study
controls may be selcted more than once for either protocol (data is recorded for each time the individ is selected, expsoure status may change in between)
if expsoure can change over time and controls are selected at set time point: time should be treated as a confounder during analyisis
if exposure can change over time, and controls are selected as cases are enrolled: a matched analysis is required. |
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Term
2 rules for contorl selction in a secondary population
VERY IMPORTNAT |
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Definition
controls should be randomly selected from non-cases in registry
controls should be selected from diagnostic categories of that, that are not associated with the exposures of interest |
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Term
| when is it appropriate to use more than one control group? |
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Definition
| when conducting methodoloigcal research |
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Term
| chart (layout) for how case controls studies are laid out |
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Definition
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