What is the Performance Measure, learning algorithm?

In order to gauge the skills of a machine learning algorithm, we must design a quantitative measure of its performance. Usually, this performance measure P is restricted to the task T being administered by the system. Accuracy is simply the proportion of examples that the model produces the right output. We will also obtain equivalent information by measuring the error rate, the proportion of examples for which the model produces incorrect output. The 0–1 loss on a specific example is 0 if it's correctly classified and 1 if it's not.