Error Rate

Synonyms

Error

Definition

Error rate refers to a measure of the degree of prediction error of a model made with respect to the true model.

The term error rate is often applied in the context of classification models. In this context, error rate = P(λ(X)≠Y ), where XY is a joint distribution and the classification model λ is a function X → Y. Sometimes this quantity is expressed as a percentage rather than a value between 0.0 and 1.0.

Two common measures of error rate for regression models are mean squared errorand mean absolute error.

The error rate of a model is often assessed or estimated by applying it to test data for which the class labels (Y values) are known. The error rate of a classifier on test data may be calculated as number of incorrectly classified objects/total number of objects. Alternatively, a smoothing function may be applied, such as a Laplace estimate or an m-estimate.

Error rate is directly related to accuracy, such that error rate = 1.0 − accuracy(or when...