Specificity
- the proportion of people without the disease that have a negative test
result
- a specific test rarely incorectly classifies people without the disease
as having the disease
- is useful to confirm or "rule in" a diagnosis
- it is rarely positive in the absence of disease
- d/(b+d)
| |
Disease X Present |
Disease X Absent |
| Test Y Positive |
a |
b |
| Test Y Negative |
c |
d |