Penetrance of a genetic variant |
Probability that traits or characteristics associated with that variant will manifest (within a specified period of time) |
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Incidence |
Number of new cases of disease occurring in a population (within a specified period of time) |
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Prevalence |
Proportion of affected individuals in a population (at a given moment of time)=incidence rate × average duration of disease |
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Sensitivity or detection rate (DR) |
Proportion of affected individuals (or those who become affected within a specified period of time) with a positive (unfavorable) screening test result |
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Specificity |
Proportion of unaffected individuals with a negative screening test result |
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False-positive rate |
Proportion of unaffected individuals with a positive screening test result=1−specificity |
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DR5
|
Detection rate for a 5% false-positive rate |
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Positive predictive value (PPV) |
Risk of disease among individuals with risk factor (with positive screening test result) (clinical impact) |
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Population attributable fraction (PAF) |
Proportion of cases that could be prevented if the risk factor was absent (the public health impact) |
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ROQ1−5
|
Relative odds of the highest fifth of the risk factor distribution compared with people in the lowest fifth |
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Number needed to treat (NNT) |
Number of people needed to treat for one success |
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Number needed to screen (NNS) |
Number of individuals needed to screen to prevent one case of disease (measure to assess the performance of screening, combining penetrance and frequency with reduction in risk of disease)=inverse of the frequency divided by the penetrance divided by the reduction in risk of disease=(1/F × p × RR) |