Herich L, Lehmacher W, Hellmich M. Drop the Likelihood Ratio. A Novel Non-electronic Tool for Interpreting Diagnostic Test Results.
Methods Inf Med 2015;
54:283-7. [PMID:
25609360 DOI:
10.3414/me14-01-0091]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 11/05/2014] [Indexed: 11/09/2022]
Abstract
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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