likelihood ratio


Also found in: Dictionary, Thesaurus, Financial, Acronyms, Encyclopedia.

likelihood ratio

usually preceded by "maximum" (that is, maximum likelihood ratio), this ratio maximizes the probability that the parameters in the ratio agree with the empirically observed data.

like·li·hood ra·ti·o

(līk'lē-hud rā'shē-ō)
The ratio of the probability of a test result among patients with a certain disease or disorder to the probability of that same test result among patients who do not have the targeted disease or disorder.

likelihood ratio

(līk′lē-hood″),

LR

A statistical tool used to help determine the usefulness of a diagnostic test for including or excluding a particular disease. An LR = 1 suggests that the test ordered neither helps to diagnose the disease in question nor helps to rule it out. Higher LRs increase the probability that the disease will be present; LRs < 1.0 decrease the probability that the disease is present.

A positive LR can be thought of as the probability that someone with a suspected condition will, accurately, have a positive test result, divided by the probability that a healthy person will, inaccurately, test positive for the disease. Mathematically this can be represented by the following equation: LR+ = sensitivity of the test/ (1− specificity of the test). A negative LR is the probability that a sick person will fail to be detected by the test, divided by the probability that a healthy person will be accurately shown by the test to have no sign of disease. Mathematically: LR− = (1 − sensitivity of the test) / specificity of the test.

likelihood ratio

The percentage of ill people with a given test result divided by the percentage of well people with the same result. Ratios near unity should not influence decisions. This useful guide to refining clinical diagnosis is little used mainly because of its complexity; The Fagan nomogram can simplify the matter.
References in periodicals archive ?
As a final technical point, the likelihood ratio statistic was unstable for change points near either end of the data.
A likelihood ratio test to detect conflicting phylogenetic signal.
Table 5 demonstrate the value of the likelihood ratio statistic after the element is incorporated inside the model.
It tracks the text of the rule better than the likelihoodist, support-based analysis, but both lead to the conclusion that relevance vel non turns on whether the likelihood ratio departs from 1.
Here I propose a method to build a high-variance scan statistic not relying on likelihood ratio.
In this situation the approach based on confidence sets using likelihood ratio tests can be used.
Likelihood Ratio Chi-Square value###1890###1802###1839###1663###1721
In the next two sections, instead, we consider the likelihood ratio test under non-Gaussian noises directly.
The result of Empirical Likelihood Ratio test (ELR) later being compared to the other method of Dette and Munk's (D-M) and showed that it is more powerful than D-M.
The likelihood ratio of each of the observed intra- operative signs is as shown in Table-IV.
Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratios (positive and negative), and efficiency of HCS compared to reference standard for diagnosis of anaemia and according to severity of anaemia; mean difference between readings obtained from HCS and reference standard and construct Bland-Altman plot with 95% limits of agreement; prevalence of anaemia and various severity of anaemia according to HCS and reference standard; mean difference between readings obtained from HCS and the reference method and construct Bland-Altman plot with 95% limits of agreement; and prevalence of anaemia and various levels of severity of anaemia according to HCS and the reference method.
Within the context of a Bayesian inference problem, they develop the theory of single-target tracking, multiple-target tracking, and likelihood ratio detection and tracking.