121:, time effects, practice effects or the natural history effect. Calculating the difference in effects between two treatment groups assumed to be exposed to a very similar array of such intervening effects allows the effects of these intervening variables to cancel out. Hence only the presence of a comparator group, which is not a feature of case-series studies, will allow a valid estimate of the true treatment effect.
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of case series studies is usually very low, due to the lack of a comparator group exposed to the same array of intervening variables. For example, the effects seen may be wholly or partly due to intervening effects such as the
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study that tracks subjects with a known exposure, such as patients who have received a similar treatment, or examines their medical records for exposure and outcome. Case series may be
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229:"Nontraditional epidemiologic approaches in the analysis of gene–environment interaction: case-control studies with no controls!"
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189:"Definition of nonconsecutive case series - NCI Dictionary of Cancer Terms"
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to investigate the association between an exposure and a
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847:. You can help Knowledge by
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369:Evidence-based medicine
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136:Consecutive case series
565:Number needed to treat
569:Number needed to harm
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408:Scientific experiment
364:Clinical study design
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21:case series
888:Categories
581:Odds ratio
573:Risk ratio
539:Prevalence
525:Occurrence
501:Case study
213:2019-07-04
147:References
102:population
641:Morbidity
629:Virulence
531:Incidence
86:case-only
805:Glossary
798:Category
675:In vitro
516:Measures
335:Overview
125:See also
113:effect,
94:genotype
84:(though
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255:8686689
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