Interesting, do you have data on Flappy Bird itself? Apple might normalize their data for those kinds of anomalies like Modern War's blip, but your Magic Piano example does show a rise in ranking both of the times they had an upswing in reviews.

Apple does seem to weight installs over time, so I wouldn't be surprised if they also weight reviews over time to catch those kinds of push notification strategies. Zach Williams's data showed something quite different than Modern War's: more of a snowballing after the initial climb, so maybe the consistent influx of reviews from the in-game button was a "normal" enough data point to get past Apple. Nobody obviously knows for sure all of the details of Apple's current algorithm.

Also not true: Apple doesn't get "Engagement" data from the app, so that part of the ranking formula is wrong.

Thanks, this is good to know.

The other large component which gets thrown around is engagement. It seems as if only companies like flurry would be able to discern this sort of information. Anything on a large scale with an embedded sdk that reports engagement really.