There’s one thing we need to remember when working with web analytics. Pageviews and events are sent via the browser over the network, via chunks of JavaScript code. There are many things that can go wrong – network is off (not a surprise for mobile users), there’s an error in some other part of our JavaScript and events are simply not sent out.
That lesson teaches us the importance of data validation. There’s a saying among data analysts: “S**t in – S**t out”. It means that if the data is inconsistent and noisy all this inconsistency will be...