Measures of Concordance and Discordance

2021 ◽  
pp. 1-10
Author(s):  
Marc Aerts
2017 ◽  
Vol 26 (3) ◽  
pp. 191-201 ◽  
Author(s):  
Rebecca J. Bennett ◽  
Dunay S. Taljaard ◽  
Michelle Olaithe ◽  
Chris Brennan-Jones ◽  
Robert H. Eikelboom

PurposeThe purpose of this study is to raise awareness of interobserver concordance and the differences between interobserver reliability and agreement when evaluating the responsiveness of a clinician-administered survey and, specifically, to demonstrate the clinical implications of data types (nominal/categorical, ordinal, interval, or ratio) and statistical index selection (for example, Cohen's kappa, Krippendorff's alpha, or interclass correlation).MethodsIn this prospective cohort study, 3 clinical audiologists, who were masked to each other's scores, administered the Practical Hearing Aid Skills Test–Revised to 18 adult owners of hearing aids. Interobserver concordance was examined using a range of reliability and agreement statistical indices.ResultsThe importance of selecting statistical measures of concordance was demonstrated with a worked example, wherein the level of interobserver concordance achieved varied from “no agreement” to “almost perfect agreement” depending on data types and statistical index selected.ConclusionsThis study demonstrates that the methodology used to evaluate survey score concordance can influence the statistical results obtained and thus affect clinical interpretations.


Author(s):  
Joanne M Foody ◽  
Lois E Lamerato ◽  
Mehul R Dalal ◽  
Jennifer Sung ◽  
Irfan Khan ◽  
...  

Introduction: The clinical and economic impact of statin intolerance (SI) in high CV risk patients is unknown due, in part, to a lack of consensus in its definition. We sought to define and validate an SI algorithm for use in an administrative database (AD) among high-CV risk patients Methods: Adults with ≥1 qualifying change (See Table 1) in statin therapy and ≥1 prior diagnosis of hyperlipidemia, hypercholesterolemia, or mixed dyslipidemia were identified from the AD of the Health Alliance Plan at Henry Ford Health System (HFHS). A sample of 1000 patients was drawn from the pool of eligible adults and stratified by high CV risk based on presence of comorbid conditions including diabetes, coronary heart disease, and peripheral artery disease. Statin utilization and adverse events data were abstracted both from the AD and the HFHS electronic medical record (EMR). SI was defined using both a primary definition inclusive of all possible statin related adverse events and a secondary definition that included only musculoskeletal events. SI was categorized as absolute (AI) or titration (TI) intolerance. The performance of the AD algorithm was assessed using measures of concordance (Cohen’s kappa [κ]) and accuracy (sensitivity, specificity, positive predictive value [PPV]) with the EMR as reference. Results: A total of 353 patients (48% female, 44% Caucasian, mean (SD) age 63 (12) years) were identified as high CV risk with 33% having a history of CHD, 77% diabetes and 2% PAD. Forty-two percent of patients were on simvastatin, 35% atorvastatin, 11% lovastatin, 7% rosuvastatin and 6% pravastatin/fluvastatin. Table 1 characterizes the validation sample. SI was identified in 19.3% and 20.7%, AI in 3.1% and 2.8%, and TI in 16.7% and 18.7% of patients in the EMR and AD, respectively. The algorithm identifying any SI had robust concordance (κ=0.73), good sensitivity (80.9%) and PPV (75.3%). The TI algorithm performed better (κ=0.78, sensitivity=86.4%, PPV=77.3%) than the AI algorithm (κ=0.56, sensitivity=54.5%, PPV=60.0%). Specificity was high (>94%) across all 3 algorithms. Conclusion: This study successfully defined SI among high-CV risk patients using an evidence-based validated algorithm. To our knowledge, this is the first such algorithm for use in AD to be made available to decision-makers.


2019 ◽  
Vol 184 (3) ◽  
pp. 762-780 ◽  
Author(s):  
Jae Youn Ahn ◽  
Sebastian Fuchs

AbstractIn the present paper, we study extreme negative dependence focussing on the concordance order for copulas. With the absence of a least element for dimensions $$d\ge 3$$d≥3, the set of all minimal elements in the collection of all copulas turns out to be a natural and quite important extreme negative dependence concept. We investigate several sufficient conditions, and we provide a necessary condition for a copula to be minimal. The sufficient conditions are related to the extreme negative dependence concept of d-countermonotonicity and the necessary condition is related to the collection of all copulas minimizing multivariate Kendall’s tau. The concept of minimal copulas has already been proved to be useful in various continuous and concordance order preserving optimization problems including variance minimization and the detection of lower bounds for certain measures of concordance. We substantiate this key role of minimal copulas by showing that every continuous and concordance order preserving functional on copulas is minimized by some minimal copula, and, in the case the continuous functional is even strictly concordance order preserving, it is minimized by minimal copulas only. Applying the above results, we may conclude that every minimizer of Spearman’s rho is also a minimizer of Kendall’s tau.


2020 ◽  
Vol 487 (1) ◽  
pp. 123951
Author(s):  
Damjana Kokol Bukovšek ◽  
Tomaž Košir ◽  
Blaž Mojškerc ◽  
Matjaž Omladič

1982 ◽  
Vol 10 (4) ◽  
pp. 1269-1276 ◽  
Author(s):  
Mayer Alvo ◽  
Paul Cabilio ◽  
Paul D. Feigin

1979 ◽  
Vol 28 (1) ◽  
pp. 3-13 ◽  
Author(s):  
G. Allen ◽  
Z. Hrubec

Estimation of the twin concordance rate for a disease often requires two stages. First, the disease is ascertained in a population or in a population sample, and such twins as are found with the disease become probands. Second, twin pairs with only one proband are further investigated and additional concordant pairs are thus discovered. A mathematical model is presented that allows for continuous variation in completeness of ascertainment in both stages, for correlation within pairs in the primary ascertainment process, and for correlation within pairs in occurrence of the disease. The concordance rate can be estimated by the proband method if secondary ascertainment is complete; other measures of concordance are accurate only if primary ascertainment is complete. A parameter analogous to the concordance rate but related to correlation in primary ascertainment can be estimated from the same data.


2019 ◽  
Vol 49 (03) ◽  
pp. 885-918
Author(s):  
Marius Hofert ◽  
Takaaki Koike

AbstractMeasures of concordance have been widely used in insurance and risk management to summarize nonlinear dependence among risks modeled by random variables, which Pearson’s correlation coefficient cannot capture. However, popular measures of concordance, such as Spearman’s rho and Blomqvist’s beta, appear as classical correlations of transformed random variables. We characterize a whole class of such concordance measures arising from correlations of transformed random variables, which includes Spearman’s rho, Blomqvist’s beta and van der Waerden’s coefficient as special cases. Compatibility and attainability of square matrices with entries given by such measures are studied—that is, whether a given square matrix of such measures of concordance can be realized for some random vector and how such a random vector can be constructed. Compatibility and attainability of block matrices and hierarchical matrices are also studied due to their practical importance in insurance and risk management. In particular, a subclass of attainable block Spearman’s rho matrices is proposed to compensate for the drawback that Spearman’s rho matrices are in general not attainable for dimensions larger than three. Another result concerns a novel analytical form of the Cholesky factor of block matrices which allows one, for example, to construct random vectors with given block matrices of van der Waerden’s coefficient.


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