We use a curving system to generate our game ranks (only for released games). Because the natural scores of our games tend to range in the 4.5-6.5 range we utilize a positive only curve for our game scores that adds to every score, but more to the games with naturally higher scores. This allows the games to stay in the same relationship and ranking with each other while giving the scores more depth and spread. The curve derives its multiplier based on how far below a "perfect 10" the number 1 game currently is. When a new game just comes out and it is getting a very high natural score, this shrinks the curve multiplier, causing every game on our list to fall in score (although they are still higher than their natural score is).
The exact formula we use for this curve is shown below:
Assume we have the following sample games. Their "natural" scores are shown here (the exact average of users scores)
STEP 1: Determine the highest game score in the list. This would be "Super Ninjas II" which has a 6.5 score.
STEP 2: Find the value half way between a perfect 10 and the top rated game. This would be 10 minus 6.5 divided by 2 then add 6.5 or ((10 - 6.5)/2) + 6.5. This value is 8.25.
STEP 3: Now find the value that you would have to multiply the #1 game by to reach this magic 8.5 number. The formula for this is 8.5 divided by 6.5 or 8.5/6.5 - which is 1.30769. This is our curve mulitplier.
STEP 4: Lastly, you multiply every score by the curve multiplier (1.30769). This means that games with larger natural scores will get a bigger boost that those with naturally lower scores.
Using the above steps our list now becomes this (also now sorted from high to low):
As you can see, the above list ends up being a lot funner to look at that the first one. The scores are spread further apart, while no game is penalized (in fact, all get some kind of increase from the curve). However, getting to the answer to the original question of "Why do all the scores crash all at once?!".
What happens is a new game releases and gets a fresh start on our list. There is a lot of excitement and fans are giving the game really good natural scores. This will typically produce a game with a much higher natural score than the rest of the pack. Let's use the very top list as a reference. Now, let's suppose that "Demongate Cincinatti" hits store shelves and MMORPG.com users are giving it a 8.5 natural score within the first few days of release. Our list would start like this:
Using the curve algorythm shown above we would now get our curve multiplier from ((10-8.5)/2) + 8.5 = 9.25 (new top score) which reduces the multiplier to 1.08823. This will drastically change the new scores. See below:
And just like that, one game completely changes the scores on the entire list. Now, normally shortly after a new game launches things will settle down and the scores will stabilize. It is just important to remember that no matter what, the score you see is actually higher than the real score of the game...so for fans angry that their favorite MMORPG just lost half a point, remember that without this curve the score would be even lower ;-)