CLARITY — Clinical Likelihood And Rule Interpretation Tool (for You)

Select a CPR study

Choose a validated clinical prediction rule from the library, then select which test or cluster to analyse.

Select a study and test above to populate the calculator.

Manual entry

Enter raw cell counts from any diagnostic accuracy study. All statistics calculate automatically.

TP Disease+, Test+

FP No disease, Test+

FN Disease+, Test−

TN No disease, Test−

Pre-test probability

30%

Contingency table

	Condition present	Condition absent	Total
Test +	—	—	—
Test −	—	—	—
Total	—	—	—

Diagnostic accuracy

Sensitivity

—

TP/(TP+FN)

Specificity

—

TN/(TN+FP)

PPV

—

TP/(TP+FP)

NPV

—

TN/(TN+FN)

LR+

—

Target >10 for strong rule-in.

Sn / (1−Sp)

LR−

—

Target <0.1 for strong rule-out.

(1−Sn) / Sp

Post-test probability

If test positive

—

Pre-test odds × LR+

If test negative

—

Pre-test odds × LR−

Import a new CPR study

Fill in the study details and add each test or cluster with its raw 2×2 cell counts. The study will be saved to the shared library and available to all CLARITY users immediately.

Condition *

Year *

Authors *

Journal

Total n *

n with condition *

Tests / clusters * (add one row per test)

Test / cluster name