Adapted from Wiki: Positive Predictive Value
Condition (pre-determined) |
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Condition Positive | Condition Negative | |||
Test Outcome |
Test Outcome Positive |
True Positive | False Positive (Type I error) |
Positive predictive value = Σ True Positive Σ Test Outcome Positive
|
Test Outcome Negative |
False Negative (Type II error) |
True Negative | Negative predictive value = Σ True Negative Σ Test Outcome Negative
|
|
Sensitivity = Σ True Positive Σ Condition Positive
|
Specificity = Σ True Negative Σ Condition Negative
|
Patients with concussion |
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Condition Positive | Condition Negative | |||
ImPACT Test Outcome |
Test Outcome Positive |
True Positive (TP) = 59 |
False Positive (FP) = 7 |
Positive predictive value
= TP / (TP + FP)
= 59 / (59 + 7) = 89.4% |
Test Outcome Negative |
False Negative (FN) = 13 |
True Negative (TN) = 59 |
Negative predictive value
= TN / (FN + TN)
= 59 / (13 + 59) = 81.9% |
|
Sensitivity
= TP / (TP + FN)
= 59 / (59 + 13) = 81.9% |
Specificity
= TN / (FP + TN)
= 59 / (7 + 59) = 89.4% |