700
edits
Changes
Measures of strength of association (view source)
Revision as of 16:46, 4 May 2011
, 16:46, 4 May 2011no edit summary
Line 24:
Line 24:
In the case of a [[Study design#Cross sectional studies|cross sectional study]], the '''[[Measures of disease frequency#Prevalence|prevalence]]''' can be estimated amongst exposed individuals as (a<sub>1</sub>/n<sub>1</sub>), and amongst unexposed individuals as (a<sub>0</sub>/n<sub>0</sub>).<br>
In the case of a [[Study design#Cross sectional studies|cross sectional study]], the '''[[Measures of disease frequency#Prevalence|prevalence]]''' can be estimated amongst exposed individuals as (a<sub>1</sub>/n<sub>1</sub>), and amongst unexposed individuals as (a<sub>0</sub>/n<sub>0</sub>).<br>
−In the case of a [[Study design#Cohort studies|cohort study]], the '''[[Measures of disease frequency#Incidence risk|incidence risk]]''' can be estimated amongst exposed individuals as (a<sub>1</sub>/n<sub>1</sub>), and amongst unexposed individuals as (a<sub>0</sub>/n<sub>0</sub>). Alternatively, the [[Measures of disease frequency#Incidence rate|incidence rate]] can be estimated as (a<sub>1</sub>/[total number of animal-time units in exposed group]) amongst exposed animals and (a<sub>1</sub>/[total number of animal-time units in unexposed group]) amongst unexposed animals.
+In the case of a [[Study design#Cohort studies|cohort study]], the '''[[Measures of disease frequency#Incidence risk|incidence risk]]''' can be estimated amongst exposed individuals as (a<sub>1</sub>/n<sub>1</sub>), and amongst unexposed individuals as (a<sub>0</sub>/n<sub>0</sub>). Alternatively, the [[Measures of disease frequency#Incidence rate|incidence rate]] can be estimated as (a<sub>1</sub>/[total number of animal-time units in exposed group]) amongst exposed animals and (a<sub>1</sub>/[total number of animal-time units in unexposed group]) amongst unexposed animals.<br>
+In the case of a [[Study design#Case control studies|case control study]], no [[Measures of disease frequency|measures of disease frequency]] can be calculated. However, the '''odds of exposure''' can be estimated amongst diseased individuals as (a<sub>1</sub>/a<sub>0</sub>), and amongst nondiseased individuals as (b<sub>1</sub>/b<sub>0</sub>).<br>