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DOI: 10.3414/ME14-01-0091
Drop the Likelihood Ratio
A Novel Non-electronic Tool for Interpreting Diagnostic Test ResultsPublication History
received:
09 September 2014
accepted:
05 January 2014
Publication Date:
22 January 2018 (online)
Summary
Objective: To present a geometric ruler to determine predictive values of binary diagnostic test results from prevalence, sensitivity and specificity without calculation.
Methods: On logarithmic scale the relationships between pre-/post-test odds and the likelihood ratio as well as sensitivity, specificity and the likelihood ratio appear as simple linear (additive) equations.
Results: Each of these additive equations can be solved geometrically in form of a ruler with three scales. By amalgamation we devise a novel non-electronic tool which omits the intermediate step of likelihood ratio determination.
Conclusions: We propose a simple geometric method to aid in interpretation of diagnostic test results for both practical and educational purposes.
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References
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