Difference between revisions of "Table measuring risk, rate and odds ratio"
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! Case Control Formulation | ! Case Control Formulation | ||
! Design | ! Design | ||
| − | ! | + | ! Controls sampled from |
|- | |- | ||
| 1-Risk ratio | | 1-Risk ratio | ||
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| + | [[File:8206.Page11 row1c2.gif-550x0.png|200px|frameless|left]] | ||
| Case cohort | | Case cohort | ||
| − | | | + | | Total study population present at beginning of study |
|- | |- | ||
| 2-Rate ratio<br /> <br /> (incidence density ratio) | | 2-Rate ratio<br /> <br /> (incidence density ratio) | ||
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| Density case control | | Density case control | ||
| <br /> People at risk at time of case disease onset | | <br /> People at risk at time of case disease onset | ||
| Line 25: | Line 29: | ||
| 3-Odds ratio | | 3-Odds ratio | ||
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| − | | Traditional case control | + | [[File:7120.Page11 row3c2.gif-550x0.png|200px|frameless|left]] |
| + | | Traditional case control (Exclusive) | ||
| <br /> People disease free throughout study period | | <br /> People disease free throughout study period | ||
|} | |} | ||
| + | |||
| + | Where: | ||
| + | Ce=Cases exposed | ||
| + | Cu=Cases unexposed | ||
| + | Ne=Population exposed | ||
| + | Nu=Population unexposed | ||
| + | PTe=Person-time exposed | ||
| + | PTu=Person-time unexposed | ||
[[Category:Case-control studies]] | [[Category:Case-control studies]] | ||
Latest revision as of 14:46, 8 April 2023
Cohort studies allow for directly measuring risk or rate of disease occurrence and their related ratio in subgroups of a population (exposed and unexposed). Case-control studies do not allow the measurement of risk or rates. They, however, allow the estimation of the risk ratio and the rate ratio. The selection of the control group is a crucial step of the study. The following table summarises the type of measures and control selection as described in the above chapter.
Measuring risk, rate and odds ratios in a case-control study, using various sampling methods for controls (Source: Rodrigues L et al. Int J Epidemiol. 1990;19:205-13)
| Measure | Definition | Case Control Formulation | Design | Controls sampled from |
|---|---|---|---|---|
| 1-Risk ratio |
|
 |
Case cohort | Total study population present at beginning of study |
| 2-Rate ratio (incidence density ratio) |
 |
 |
Density case control | People at risk at time of case disease onset |
| 3-Odds ratio |
 |
 |
Traditional case control (Exclusive) | People disease free throughout study period |
Where: Ce=Cases exposed Cu=Cases unexposed Ne=Population exposed Nu=Population unexposed PTe=Person-time exposed PTu=Person-time unexposed
Root > Assessing the burden of disease and risk assessment > Field Epidemiology > Methods in Field Epidemiology > Types of Study > Case-control studies
