You might have noticed, I am obsessed with game sales. I know it would be easier to enjoy gaming without watching the market all the time, but I can’t. And for digital-only games, the blackout is total. How to find out? One day I came up with partial, but interesting method.

Since PSVita and PS4, the unlocking ratio of trophies is public. You just have to open your trophy list to check how the Playstation Nation performs on any trophy. The PSN tells you what percentage of the game’s owners has unlocked a trophy. Nice info, but a percentage alone don’t lead us anywhere. Wouldn’t there be some actual figure to calculate from out there?

Yes, there is. PSN Profiles publishes the actual number of players having unlocked a trophy! Then we reason like this : people who have unlocked a trophy on PSN Profiles also have unlocked it on the PSN, so they necessarily belong to the percentage displayed on the PSN. Therefore, we can make a connection between this percentage and PSN Profiles members, since they are the same persons. In order to have the most precise calculation, we have to pick the rarest trophy, which is the platinum since it supposes to have unlocked all the others. Please look at Neptune-sensei’s formula.

Before analyzing it, let’s define some variables

S = Total number of owners of a game. In case of a digital only title, the total sales since it can neither be lent, nor traded.

Smin = Minimum but certain sales of a game

P = Number of platinum obtained for one game

Pp = Number of platinum on PSN Profiles for one game

tP = Unlocking rate of a platinum

The platinum rate is calculated by dividing the number of platinums by the total number of players, so tP = S/P. Then S = P/tP

Here we need to exercise extreme caution, because not everyone is registered on PSN Profiles. The website has some 2.5m members on several dozens of millions of PSN accounts worldwide. Here’s the snag : the error margin dramatically increases depending on how many platinums are NOT registered on PSN Profiles. We can therefore only calculate the minimum number of owners of the game. Mathematically, P > Pp, so Smin = Pp/tP < S

Let’s take Hatsune Miku Project Diva f, very interesting example since this Vita version has a distinct trophy list from the PS3 one. Platinum rate is 8.1% as SonicDX indicates, and there are 1574 platinums on PSN Profiles. Project Diva f PSVita has thus sold a minimum amount of 1574/0,081 = 19432 units.

As for Sword Art Online Hollow Fragment (216 platinums and an abysmal 0.2% rate), we get 108’000 sales at least. This is quite under its actual sales, because BandaiNamco had stated it sold 570’000 copies worldwide, including some 300’000 in the West by subtracting the Japanese sales. The error margin is therefore quite large and we must consider the fact that actual sales are several times higher than the figure we have.

With Ichikyo57’s data, we can establish the following minima.

Hyperdimension Neptune ReBirth1 → 1818/0,084 = 21643

Atelier Rorona Plus → 258/0,042 = 6143

Atelier Totori Plus → 478/0,031 = 15419

Atelier Meruru Plus → 169/0,025 = 6760

Quite a good score for Hatsune Miku, the Vita version having been released much mater than the PS3 one and being identical by the way. Nice performance also for ReBirth1, the minimum sales suggesting final figures close to the Japanese ones. Atelier is bearish, but Atelier Totori had triggered an unusual hype by its unexpected arival on the Playstation Store.

That’s the deal. True, the reliability of the formula is limited but it’s a good indication to assess the situation of digital-only games in the economic environment.