## Top PDF Receiver Operating Characteristic Curves:

### Statistics review 13: Receiver operating characteristic curves

When the cut-off value for a continuous diagnostic variable is increased (assuming that larger values indicate an increased chance of a positive outcome), the proportions of both true and false positives decreases. These proportions are the sensitivity and 1 – specificity, respectively. A graph of sensitivity against 1 – specificity is called a receiver operating characteristic (ROC) curve. Figure 1 shows the ROC curve for lactate using the cut-off values given in Table 4. The preferred method is to join the points by straight lines but it is possible to fit a smooth curve from a parametric model. A perfect test would have sensitivity and specificity both equal to 1. If a cut-off value existed to produce such a test, then the sensitivity would be 1 for any non-zero values of 1 – specificity. The ROC curve would start at the origin (0,0), go vertically up the y-axis to (0,1) and then horizontally across to (1,1). A good test would be somewhere close to this ideal. If a variable has no diagnostic capability, then a test based on that variable would be equally likely to produce a false positive or a true positive:

### Accuracy of logistic models and receiver operating characteristic curves

We are able to use the retrospective and prospective ROC curves to show that the 'shrunk' estimates can produce predictors which have better discriminatory power than the model or data a[r]

### Testing the significance of crossover receiver operating characteristic curves in the presence of multiple markers

In multivariate classification, attention is required for those reference values of markers which provide at least a moderate amount of classification. In usual context of assessing the performance of a test, scores which are nearer to reference value are given the same amount of weightage as that of the scores farther from reference value. The area under the curve (AUC) so computed will be contaminated, and the true accuracy or the actual performance will be masked. This misleads the interpretation of the measures of ROC as well as the optimal threshold. In general, let us consider two tests A and B for better identification of a particular abnormality in individuals. Suppose that the curves of tests A and B cross each other and have at most similar accuracies. Under these circumstances, it is very difficult to notify a better test which has more ability to distinguish status of individuals. To resolve this issue, a new testing procedure is given in a parametric sense which makes use of the modified version of AUC rather than the conventional AUC of MROC curve proposed by Sameera et al. (4). Further, the role of sample size in distinguishing the crossover MROC curves is also considered, and numerical illustrations are accommodated by both real and simulated environments.

### The differentiation of pancreatic neuroendocrine carcinoma from pancreatic ductal adenocarcinoma: the values of CT imaging features and texture analysis

4 Receiver operating characteristic curves of the contrast ratio at the arterial phase (AER) and portal phase (PER) (A), and texture parameters (uniformity, uni; entropy, ent) (B) at por[r]

### Approaches to denote treatment outcome: Clinical Significance and Clinical Global Impression compared

F I G U R E 3 Receiver operating characteristic curves and a selection of change threshold levels (Positive Reliable Change Index values) comparing two operating characteristics: dichoto[r]

### Do Skinfold Measurements Provide Additional Information to Body Mass Index in the Assessment of Body Fatness Among Children and Adolescents?

RESULTS. For children aged 5 to 18 years, BMI-for-age, triceps skinfold-for-age, and subscapular skinfold-for-age each performed equally well alone in the receiver operating characteristic curves in the identification of excess body fat defined by either the 85th or 95th percentile of percentage of body fat by dual-energy radiograph absorptiometry. However, if BMI-for-age was already known and was ⬎ 95th percentile, the additional measurement of skinfolds did not significantly increase the sensitivity or specificity in the identification of excess body fat.

### From Power Curves to Discriminative Power: Measuring Model Performance of LGD Models

Measuring model performance of rating systems is a major task for banks. The concept of discrimination, i.e. the discriminative power, is used in credit risk modeling to assess the quality of a risk model concerning the separation of extreme events. For PD models CAP (Cumulative Accuracy Profile) or ROC (Receiver Operating Characteristic) curves are used to build a quantity called Accuracy Ratio, which is used to measure the discriminative power. These ideas are well known and broadly used in practice. Although such a measure is also desirable for models of the loss given default (LGD models), it is not documented in the literature. In this note we close this gap. We develop a measure for the discriminative power of LGD models based on Lorenz curves. We study first properties and introduce some alternatives for its cal- culation from a practical point of view.

### The Outcome of Monochorionic Diamniotic Twins Discordant at 11 to 13+6 Weeks’ Gestation

and known pregnancy outcome between August 2003 and August 2012 were included. Receiver operating characteristic curves were used to determine the ideal NT and CRL discordances cut-off points that max- imized the ability to predict adverse outcome, which was defined as any of: death of one or both twins, twin-to-twin transfusion syndrome, or estimated fetal weight or birth weight discordances ≥25%. Results: Of the 89 cases, 20 (22.5%) had at least one adverse outcome. NT discordance was more discriminatory of adverse outcome than was CRL discordance. The optimal values for predicting any adverse outcomes for NT were > 23.7% and for CRL > 3.5%. The positive predictive values for NT (52.4%) and CRL (29.8%) screening were relatively low; however, the lack of either NT or CRL discordances was more reassuring, with negative predictive values of 86.8% and 86.4%, respectively. Conclusions: NT discordance is more predic- tive for adverse fetal outcome in MCDA twins than CRL discordance. Neither NT nor CRL discordance are likely to modify the intensive monitoring required for these very high-risk pregnancies.

### Elevated plasma thrombomodulin and angiopoietin 2 predict the development of acute kidney injury in patients with acute myocardial infarction

Table 2 Acquisition of the areas under the receiver operating characteristic curves for day 1 plasma levels of angiopoietin-2 and thrombomodulin to predict development of acute kidney in[r]

### <p>Combination of the CAGE and serum gamma-glutamyl transferase: an effective screening tool for alcohol use disorder and alcohol dependence</p>

Notes: The combined CAGE and GGT scores were calculated by equations derived from multiple logistic regression analyses after adjustment for age and gender. Abbreviations: AUROC, area under the receiver operating characteristic curves; NC, normal control; PD, problem drinking; AUD, alcohol use disorder; AD, alcohol dependence; AUDIT, alcohol use disorders identiﬁcation test; CAGE, cutting down, annoyance by criticism, guilty feeling, and eye-openers; GGT, gamma-glutamyl transferase; CAGE+GGT, combination of CAGE and GGT.

### Prediction and validation of protein–protein interactors from genome-wide DNA-binding data using a knowledge-based machine-learning approach

Downloaded from http://rsob.royalsocietypublishing.org/ on September 27, 2018 a partition data assess performance of models receiver operating characteristic curves d RANDOM 3 rsob.royal[r]

### Validation of the Saint George’s Respiratory Questionnaire in Uganda

obtained via linear regression, controlling for age, sex and height. Validity of SGRQ total score and component categories as predictors of COPD status in the commu- nity was assessed via unadjusted logistic modelling and receiver operating characteristic (ROC) curves. Based on this outcome, a cut point was chosen and agreement between SGRQ and COPD status using this cut point was established via Fleiss’ kappa test. The association between SGRQ score and COPD severity as defined by per cent predicted FEV 1 was assessed via Pearson correla-

### A Gibbs Sampler for Learning DAGs

Figure A16: ALARM data, receiver operating characteristic (ROC) curves for each of 10 independent MCMC runs for each MCMC sampler, and point estimates for the constraint-based methods.. [r]

### Mammographic phantom images using receiver operating characteristic analysis

Quantitative imaging has an important role in developing image analysis methods to extract quantitative data more accurately in detection and diagnosis (Giger, 2008). Receiver Operating Characteristic (ROC) analysis is one of the imaging analysis methods to compare the accuracy of two or more imaging modalities. The ROC curve represents sensitivity (True Positive Fraction) and specificity (True Negative Fraction). ROC analysis evaluates the plots by calculating the area under the curves. The mammographic images are scored based on subjective interpretation by observers. Many researchers had proved that quantitative diagnostic assessments from ROC curves could provide valuable feedback to improve diagnostic performance.

### Evaluating cutpoints for the MHI 5 and MCS using the GHQ 12: a comparison of five different methods

Receiver Operating Characteristic ROC curves were used to compare the scales and define cutpoints for the MHI-5 and MCS, using the following optimisation criteria: the Youden Index, the [r]

### Serum Helicobacter pylori FliD antibody and the risk of gastric cancer

FliD and CagA are important virulence factors of H. pylori. We aimed to evaluate the screening values of FliD and CagA for gastric cancer (GC). Serum samples were obtained from 232 cases and 266 controls in a case-control study. Unconditional multivariate logistic regression with odds ratios (ORs) and 95% confidence intervals (CIs) was used to analyze the relationships between FliD, CagA and GC. The sensitivities, specificities and receiver operating characteristic (ROC) curves were calculated. Finally, the combined screening values of FliD, FlaA, NapA and CagA were assessed based on discriminant analysis. In all subjects, the associations of FliD and CagA with GC were evident with ORs (95% CIs) of 7.6 (4.7-12.3) and 2.5 (1.6-3.8), respectively (*p<0.001). The areas under ROC curves (AUCs) for FliD and CagA were 0.800 and 0.653, respectively. The AUC for the combination of FliD, FlaA and NapA was 0.915, which represented an increase of 0.115 over that of FliD alone (*p<0.001). These findings indicate that the FliD antibody is associated with GC and could exhibit high validity as a biomarker in screening for GC patients. The combination of FliD, FlaA and NapA improved the screening validity.

### A Locally Adaptable Iterative RX Detector

Copyright © 2010 Yuri P. Taitano et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We present an unsupervised anomaly detection method for hyperspectral imagery (HSI) based on data characteristics inherit in HSI. A locally adaptive technique of iteratively refining the well-known RX detector (LAIRX) is developed. The technique is motivated by the need for better first- and second-order statistic estimation via avoidance of anomaly presence. Overall, experiments show favorable Receiver Operating Characteristic (ROC) curves when compared to a global anomaly detector based upon the Support Vector Data Description (SVDD) algorithm, the conventional RX detector, and decomposed versions of the LAIRX detector. Furthermore, the utilization of parallel and distributed processing allows fast processing time making LAIRX applicable in an operational setting.

### Coronary Computed Tomography Angiography-Specific Definitions of High-Risk Plaque Features Improve Detection of Acute Coronary Syndrome: Results From the ROMICAT II Trial

Continuous data are presented as mean ± standard deviation or median with 25th and 75th percentile, and categorical or ordinal variables are presented as absolute and relative frequencies. On a per patient level, comparisons between groups were performed with an independent student t-test or the Wilcoxon rank-sum test for continuous variables, Fisher’s exact test for categorical variables, and Wilcoxon rank-sum test for ordinal variables. On a segmental level, comparisons between groups were performed using univariable multilevel mixed-effects logistic regression models that account for the group structure (i.e. multiple segments per patient) and thus possible autocorrelation effects in the data. To evaluate interobserver agreement among four readers, intraclass correlation coefficient (ICC) was calculated using two-way random-effects models. To determine co-linearities among all HRP features, we assessed Spearman’s rank correlation coefficients. Uni- and multivariable multilevel mixed-effects logistic regression analysis were performed to identify determinants for culprit lesion within ACS patients and determinants for ACS among all patients. In the multivariable model we included remodeling index, minimal luminal area (mm 2 ), plaque burden (%), TCFA equivalent – Low HU plaque volume <30 HU (mm 3 ) and lesion length. The discriminatory capacity of the dichotomized HRP thresholds for the prediction of culprit lesion and ACS was assessed using the area under curve (AUC) 27 . Multivariable logistic regression models were used to calculate receiver operating characteristic (ROC) curves. A two-tailed p-value of <0.05 was considered statistically significant. All statistical analyses were performed using Stata 13.1 (Stata- Corp LP, College Station, Texas). The complete source data from the Rule Out Myocardial Infarction/Ischemia Using Computer Assisted Tomography (ROMICAT) II trial are publicly available in accordance with the data sharing policy of the National Institutes of Health and can be used for the purposes of reproducing the results or replicating the procedures.