Operating characteristic curve

In test planning, the number to be placed on test n and the number of failures rmust be deterrnined. The operating characteristic curves in Reference 18 can be used to specify the test, and to control the errors. 

Fig. 2 A receiver operator characteristic curve reproduced from PubMedCentral http //www. pubmedcentral.nih.gov/articlerender.fcgi artid=1065080 and [16]...

Each sampling plan should be accompanied by an operating characteristics curve (or OC curve). The curve describes the probability of acceptance of a lot as a function of its actual quality. It shows what any particular sampling plan can be expected to achieve in terms of accepting or rejecting lots. 

Table 3.3 shows the operating characteristics for a normal inspection level sampling plan with a sample size (i.e. number of items examined) of n = 200 at three different AQLs. This table shows that if a product has 3% nonconforming items (p) then, using an AQL of 2.5%, approximately 95% of lots would be expected to be accepted. Operating characteristics curves are given in ISO 2859-1. 

The term in-process testing is synonymous with process control. From an engineering perspective tests at the end of a process do not provide any direct means to keep a process under control. It is well recognized that such tests simply accept or reject lots and depending on the operating characteristic curve of a test accepted lots are no better than the rejected ones (14). 

Economy of testing is gained thru the reduced sample sizes resulting from the integration of all available data. The users and developers risks are estimated thru the use of operating characteristics curves, which take into account how far the projectile has to go, the kill factor and the like... 

Fig. 6 Test set receiver operator characteristic curves for M. tuberculosis Bayesian models, (a) Southern Research Institute data for >100,000 molecules (1,702 actives), (b) Novartis data for 248 molecules (34 actives), (c) FDA-approved drugs, 2,108 molecules (21 actives) (17,29)...

LLD, lower limit of detection 99th, 99th percentile reference limit ROC, receiver operator characteristic curve optimized cutoff 10% Cy lowest concentration to provide a total imprecision of 10%. 

ROC curve Receiver Operating Characteristics curve. A graphical technique of evaluating the performance of a classifier the plot of sensitivity by 1 - specificity (see sensitivity/specificity). 

Discrimination can be summarized by various single statistics, such as the area under the receiver operating characteristic curve (or the equivalent C statistic), measures, or the d statistic, although all of these measures have limitations (Royston and Sauerbrei 2004 Altman and Royston 2007 Lewis 2007). 

Wintermark M, Flanders AE, Velthuis B, Meuh R, van Leeuwen M, Goldsher D, Pineda C, Serena J, van der Schaaf I, Waaijer A, Anderson J, Nesbit G, Gabriely L Medina V, Quiles A, Pohlman S, Quist M, Schnyder P, Bogousslavsky J, Dillon WP, Pedraza S (2006) Perfusion-CT assessment of infarct core and penumbra. Receiver operating characteristic curve analysis in 130 patients suspected of acute hemispheric stroke. Stroke 37 979-985. 

FIGURE 34 (A) ROC plot on AE for lactose AUC of classifier at 0.% and (B) AE energy distributions for capped and non-cappcd tablets. Abbreviations AE. acoustic emission ROC. receiver operating characteristic curve. Source From Ref. 166. 

Figure 2. Operating characteristic curves for cam, peanut butter, raw...

Figure 3. Operating characteristic curves for USDA/FGIS collaborative study of aflatoxin test kits.

Figure 15-2 Receiver operating characteristic curve of prostate-specific antigen (PSA). Each point on the curves represents a different decision level.The sensitivity (true-positive rate) and I— the specificity (false-positive rate) can be read for Tests A and B. The true-positive and false-positive rates are demonstrated using 4 and IO Xg/L as decision thresholds.

Figure S-3 Receiver operating characteristic curves of prostatic acid phosphatase (PAP) and prostate-specific antigen (PSA) assays for patients with benign prostatic hyperplasia and prostatic carcinoma. Because the PSA assay curve is above the PAP assay curve at ail points, the PSA assay is the better assay for the patients tested.

Shultz EK. Multivariate receiver-operating characteristic curve analysis Prostate cancer screening as an example. Clin Chem 1995 41 1248-55. 

Although most methods very readily identify severe, uncomplicated iron deficiency, the large number of tests that have been advocated for the diagnosis of iron deficiency is a reflection of the fact that none by itself is sufficient to detect mild iron deficiency or iron deficiency in a clinically complex setting. Receiver operator characteristic curves (ROC) confirm that no one method is superior, and that different studies differ in the conclusions that they draw regarding advantages of one method over another. ... 

Figure 44-16 Receiver operating characteristic curves to establish the best discriminator limit for cardiac troponin T (cTnT) for predicting AMI.The number of true positives (/-axis) and false positives (x-axis) are reported in relation to time (h) after the onset of symptoms.The best discriminating point for cTnT is 0.20 Xg/L at 9 hours after the onset of chest pain. (Reprinted by permission of Elsevier Science from Burlina A, Zaninotto M, Seccfiiero S, Rubin D.Accorsi F. Troponin T as a morfcer of ischemic myocardial injury. Clin 6/ocbem I994 27 t 13-21. Copyright 1993 by Canadian Society of Clinical Chemists.)...

The Receiver Operator Characteristic curve (ROC curve) is a graphical plot of the sensitivity Sn versus false positive rate FPR for a binary classifier system as its discrimination threshold is varied. The ROC curve can also be represented equivalently by plotting the fraction of true positives (TP) versus the fraction of false positives (FP) (Figure C3). ROC analysis provides tools to select possibly optimal classification models. 

Receiver Operator Characteristic curve classification parameters... 

One measure of accuracy is the likelihood ratio (LR) [17]. The likelihood ratio is based on the relationship between the true positive fraction and the false positive fraction. Thus, LR = TPF/FPF. Substituting terms, the LR = sensitivity/(1-specificity). Receiver-operating characteristic curves are graphical summaries of likeli-... 

This equation describes an operating characteristic" curve—the relationship between the percentage of contaminated items in the universe and the probability of accepting or rejecting the universe on the basis of finding at least one contaminated item in a sample of a specified size (N). 

Gardner, 1. A., and M. Greiner. 2006. Receiver-operator characteristic curves and likelihood ratios Improvements over traditional methods for the evaluation and application of veterinary clinical pathology tests. Veterinary Clinical Pathology 35 8-17. 

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