True negative rate

True negative rate probability that the test result is negative when the analyte is not present, A (i.e. equal or below the specification limit, respectively)... 

In clinical chemistry and medical diagnostics the true positive rate is called sensitivity rate and the true negative rate specificity rate (O Rangers and Condon [2000]) without any relation to the general definition of the terms sensitivity and specificity and their use in analytical chemistry (see Sects. 7.2 and 7.3). 

PPR is the probability of obtaining positive responses, TPR true positive rate (Eq. 4.48), TNR true negative rate (Eq. 4.49), FPR false positive rate (Eq. 4.50), FNR false negative rate (Eq. 4.51), X/ and xu are the lower and upper limits of the unreliability region... 

These are well-known classification parameters true positive rate (p ), false positive rate (pnx), true negative rate (qnx), and false negative rate (qK). They can be easily obtained from the previous computations where we calculated the number of taxon and nontaxon members in each interval. For example, to calculate the true positive rate, we sum the number of taxon members in intervals above the hitmax, plus half of taxon members in the hitmax interval and divide this by the total number of taxon members in the sample. To calculate the false negative rate, we sum number of taxon members in intervals below the hitmax, plus half of the taxon members in the hitmax interval and divide this by the total number of taxon members in the sample. 

The data on the true positive and true negative rates in conjunction with the drug use in the target population can be used to calculate the predictive value of the test. The predictive value is the percentage of true positives in a positive test population. 

Specifrcity d/(b + d) Fraction of negatives correctly predicted negative, true negative rate... 

The true-negative rate is the probability that a participant does not have the disease given that she or he has tested negative. This is denoted by P(D- T-) and is also referred to as predictive value negative. The complement, 1 - P( )- r-) = P(D+ r-), is the falsenegative rate. 

Show that the true negative rate of a diagnostic test is a function of the sensitivity and specificity of the test and the prevalence of the disease. 

Sn being the sensitivity (or the true positive rate, TPR or recall), Sp the specificity (or the true negative rate, TNR), FNR the false negative rate, FPR the false positive rate, PPV the positive predictive value (or precision), and NPV the negative predictive value. 

Specificity the probability of correctly identifying disease-free persons. Specificity is the proportion of truly nondiseased persons who are identified as nondiseased by the screening test. This is also known as the true negative rate. ... 

Specificity is the measure of the true negative rate, which represents the ratio of true negatives (TN) to the total number of inactive compounds. The number of inactive compounds corresponds to both true negatives (TN) and false positives (FP) ... 

The ROC curve can also be constructed as a plot of true positive rate (sensitivity) versus true negative rate (specificity) instead of versus false positive rate... 

Successful VS rehes on the abihty to discriminate between active and inactive compounds in order to provide a set of compounds for experimental screening that is highly emiched in active molecules [93]. Sets of known active and inactive compounds are needed for the assessment of VS approaches. Decoys are molecules that are presumed to be inactive against a target, which can be used when too few inactive compounds are available for such testing [94]. Many metrics are currently used to quantify the effectiveness of a VS [95]. The enrichment factor (EF) represents one of the most prominent metrics in VS. EF measures how maity more active compounds are found within a defined early recognition fraction of the ordered list relative to a random distribution. Sensitivity and specificity are also descriptors that assess the enrichment of active molecules from a database. Sensitivity (Se, or true positive rate) describes the ratio of the number of active molecules found by the VS method to the number of all active compounds in the database. Specificity (Sp, or true negative rate) represents the ratio of the number of inactive compounds that were not selected by the VS protocol to the number of all inactive molecules included in the database [93]. 

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