Please enter data into the 2 by 2 table
to determine the likelihood ratio
Positive Likelihood Ratio:
Negative Likelihood Ratio:
The likelihood ratio for a test result compares the likelihood of that result in patients with disease to the likelihood of that result in patients without disease.
So how much do LRs change disease likelihood?
Impact on Likelihood
Positive Likelihood Ratio= (a/(a+c)) / (b/(b+d))
Negative Likelihood Ratio= (c/(a+c)) / (d/(b+d))
- or -
Positive Likelihood Ratio= (sensitivity)/(1-specificity) = TP/FP
Negative Likelihood Ratio= (1-sensitivity)/(specificity) = FN/TN
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