I think that the ratio has substantial variance; it has also changed over time, somewhat dramatically, as Valve/Steam have made changes & added features/UI/UX t

I think that the ratio has substantial variance; it has also changed over time, somewhat dramatically, as Valve/Steam have made changes & added features/UI/UX that I suspect are intended to increase the % of users who leave reviews. About 5 years ago, the belief was that the ratio was in the realm of 1 : 50-100 -- based on my own data & data shared with me by other indies. Even then, there was substantial variance; genre, theme, price point, developer involvement, discounts, review score (proxy for player experience/overall game quality), etc -- were some of the key variables that I believed were having a significant impact on review-to-sales ratio variance between games. Over time, changes to the UX have been made (by Valve/Steam) which appear to have increased the rate at which players leave reviews -- quite substantially, it seems. On the whole, I think that a far higher percentage of players are leaving reviews now (ie a lower review-to-sale ratio), but I also believe that the variance is even higher now than it was before. It's still helpful for making estimates, but I don't think it's as highly-correlated as it once was (~5yr ago it was much more consistent & highly correlative).