Anyone have any market data that would indicate the ratio of reviews to downloads in the iPhone App Store? Does the ratio of reviews to downloads change significantly if an app is free or paid?
There is no official number released for your question but... Keeping that in mind you can sometimes make a good "guesstimate" about the ratio. You need to follow the mobile app market as a whole. Once in a while a big name would say something like "We have 10million downloads up to date" or something like that.
The short answer would be that the ratio is around 180-200:1
Again it depends on the app, whether it is paid or free and a number of other factors.
Apple only prompts users to leave a review when the app is removed. Not the best time to ask for a favourable review. Other apps prompt users based on usage in their apps. Since there is no "Norm" It's hard to tell.
A way to try and work it out would be to look at the game center for a popular app and see number of "players" (users). then look at reviews in the app store. This would give you some kind of ratio.
The review system is utterly flawed and Apple doesn't care.
The Apple Appstore is the very worst that could ever happen to devs. Stay clear of it if you can.