Ratio metrics

1 · Erik Bernhardsson · Jan. 23, 2014, 5 a.m.
We run a ton of A/B tests at Spotify and we look at a ton of metrics. Defining metrics is a little bit of an art form. Ideally you want to define success metrics before you run a test to avoid cherry picking metrics. You also want to define a metric that has as high signal to noise ratio. And of course, most importantly, your metric should ideally correlate to high level business impact as much as possible. One pet peeve I have is metrics defined as ratios. While some of them are useful, there a...