Freakonomics has a great episode on Uber and their dataset: https://freakonomics.com/podcast/why-uber-is-an-economists-d...

...which makes me think that Uber ratings may have less to do with the driver and more to do with the person giving the rating. I, for one, struggle giving people a bad review knowing that their livelihood depends on it — it's either 5 stars or crickets.