# What is the purpose of the generalization error bound?

I could not understand what is the purpose of the generalization error bound, why do we need to calculate it?!. How does the generalization error bound work with 1-nearest neighbour algorithm ?. Does this mean, there is a guarantee that the error rate will be less than 1-nn on test set. Please see the image for the generalization error bound that I could not understand it.

• @Dougal do you know about it ?! – miss Ran Dec 2 '19 at 11:11