How a rate button can actually improve your mobile app rating

When I decided to redesign my Android Spirit Level this summer, I was wondering wether or not I should add a "Rate" button to invite users to rate the Bubble Level application.

What I was expecting was more feature requests and a better user feadback. I was also concern about how such a button could annoy users... In the long term, would it lead to a better user rating or a lower user rating ? Here is the answer :

Evolution of the app overall rating

Since the update of late august that added the rate button in the app, overall rating of the app increased faster than before... User feedback was also better because of the easy way to provide it when you see something wrong, something missing or something to improove. In the contrary, number of rates per month does not increase as expected :

Rates per month per value and average rating

I'm not sure wether or not this stat reflect rate that get updated by users... But to provide you with more stats, the rate button has a click to rate rate ;-) of 1 generated rate out of 16 clicks... which is quite low but sufficient to increase the overall rating of the app.