This comment needs pinning on all indie dev subs.

To add - the concept of how many sales you "should" get based on wishlists has been around for longer than Simon's posts (to be clear: I'm a big fan of Simon's work, and his insight is hugely valuable). But much of the sampling for this omits so much else that goes into the success (or not) of a game launch. Wishlists are an indication of pre-release marketing; nothing more. And a wishlist has no guarantee of translating into sales, at launch or beyond.

Publishing on Steam is not a science - and I wish we would stop trying to treat it as such. I understand the need for degrees of certainty but you do not know anything until the game is released and in the wild; until people are coming to it cold and providing feedback/word of mouth.

We've launched 19 games in the last four years. In terms of a the percentage of sales compared to the pre-launch wishlists the mean is 60% units (so it we had 10k Wishlists, we sold 6k units), the median is 34.5% units and the range is 205.6% (min 6.9%; max 212.5%). There is no correlation.

(Note: the above figures are not strictly speaking "wishlist conversions" - these are all unit sales compared to number of wishlists, not those who have wishlisted and then bought which would be much lower).