# What is the top-5 error rate in ILSVRC challenge?

While I'm reading the deep learning book, I came across something as "top-5 error rate". I want to know what is it really about and how it is evaluated in ILSVRC (ImageNet Large Scale Visual Recognition challenge) ?

So, for example, if a test image is a picture of a Persian cat, and the top 5 predicted classes in order are [Pomeranian (0.4), mongoose (0.25), dingo (0.15), Persian cat (0.1), tabby cat (0.02)], then it is still treated as being 'correct' because the actual class is in the top 5 predicted classes for this test image.