At Magnetic we use logistic regression and Vowpal Wabbit in order to determine the probability of a given impression resulting in either a click or a conversion. In order to decide which variables to include in our models, we need objective metrics to determine if we are doing a good job. Out of these metrics, only the computation of lift quality (in it’s exact form) is not easily parallelizable. In this post, I will show how the computation of lift quality can be re-ordered to make it distributable.