PAPIs Latam 2019

After modeling and validating both with automatic and internal manual tests, we deploy a recommendation system. But did we randomize properly the testing groups? Adding a feature to one page, but not another, will already imply in selection bias. In this presentation we will quickly present a neural network based recommender, but focus on the issues faced when (a) defining our randomized trial test (b) selecting the test and control groups (c) coping with our inherent web based selection bias and (d) defining which statistical test to apply and (e) how to interpret its results.