scholarly journals Nonparametric estimation of distributions and diagnostic accuracy based on group‐tested results with differential misclassification

Biometrics ◽  
2020 ◽  
Vol 76 (4) ◽  
pp. 1147-1156
Author(s):  
Wei Zhang ◽  
Aiyi Liu ◽  
Qizhai Li ◽  
Paul S. Albert
Keyword(s):  
Diagnostic Accuracy ◽  
Nonparametric Estimation ◽  
Differential Misclassification ◽  
Estimation Of Distributions

Nonparametric estimation and inference for polytomous discrimination index

2017 ◽  
Vol 27 (10) ◽  
pp. 3092-3103 ◽  
Author(s):  
Jialiang Li ◽  
Qunqiang Feng ◽  
Jason P Fine ◽  
Michael J Pencina ◽  
Ben Van Calster
Keyword(s):  
Diagnostic Accuracy ◽  
Nonparametric Estimation ◽  
Asymptotic Properties ◽  
Real Data ◽  
Discrimination Index ◽  
Simulation Studies ◽  
Finite Sample ◽  
Nonparametric Estimators ◽  
Nonparametric Approach ◽  
Accuracy Measure

Polytomous discrimination index is a novel and important diagnostic accuracy measure for multi-category classification. After reconstructing its probabilistic definition, we propose a nonparametric approach to the estimation of polytomous discrimination index based on an empirical sample of biomarker values. In this paper, we provide the finite-sample and asymptotic properties of the proposed estimators and such analytic results may facilitate the statistical inference. Simulation studies are performed to examine the performance of the nonparametric estimators. Two real data examples are analysed to illustrate our methodology.

Clausal Density Between Ages 4 and 9 Years for the Edmonton Narrative Norms Instrument: Reference Data and Psychometric Properties

2020 ◽  
pp. 1-15
Author(s):  
Ling-Yu Guo ◽  
Phyllis Schneider ◽  
William Harrison
Keyword(s):  
Diagnostic Accuracy ◽  
Psychometric Properties ◽  
Language Impairment ◽  
Reference Data ◽  
Reliability And Validity ◽  
Correlation Coefficients ◽  
Criterion Validity ◽  
Likelihood Ratios ◽  
Generation Task ◽  
Sensitivity Specificity

Purpose This study provided reference data and examined psychometric properties for clausal density (CD; i.e., number of clauses per utterance) in children between ages 4 and 9 years from the database of the Edmonton Narrative Norms Instrument (ENNI). Method Participants in the ENNI database included 300 children with typical language (TL) and 77 children with language impairment (LI) between the ages of 4;0 (years;months) and 9;11. Narrative samples were collected using a story generation task, in which children were asked to tell stories based on six picture sequences. CD was computed from the narrative samples. The split-half reliability, concurrent criterion validity, and diagnostic accuracy were evaluated for CD by age. Results CD scores increased significantly between ages 4 and 9 years in children with TL and those with LI. Children with TL produced higher CD scores than those with LI at each age level. In addition, the correlation coefficients for the split-half reliability and concurrent criterion validity of CD scores were all significant at each age level, with the magnitude ranging from small to large. The diagnostic accuracy of CD scores, as revealed by sensitivity, specificity, and likelihood ratios, was poor. Conclusions The finding on diagnostic accuracy did not support the use of CD for identifying children with LI between ages 4 and 9 years. However, given the attested reliability and validity for CD, reference data of CD from the ENNI database can be used for evaluating children's difficulties with complex syntax and monitoring their change over time. Supplemental Material https://doi.org/10.23641/asha.13172129

1956: Does Increasing the Number of Cores of Prostate Biopsy Improve Diagnostic Accuracy? Indications and Morbidity

2007 ◽  
Vol 177 (4S) ◽  
pp. 649-649
Author(s):  
Ponnambalam Chandrasekar ◽  
Jeremy Raynard ◽  
Abdul Sayed ◽  
Faiyaz Kapasi ◽  
Jaspal S. Virdi ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Prostate Biopsy

Abstract #130 Diagnostic Accuracy of Dexamethasone Suppression Test: Additive Value of Free Cortisol and Dexamethasone Measurements

2019 ◽  
Vol 25 ◽  
pp. 19
Author(s):  
Ravinder Jeet Kaur ◽  
Shobana Athimulam ◽  
Molly Van Norman ◽  
Melinda Thomas ◽  
Stefan K. Grebe ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Dexamethasone Suppression Test ◽  
Free Cortisol ◽  
Suppression Test ◽  
Dexamethasone Suppression
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