# How is TDS wifi-rating calculated?

Thread in 'Discussion' started by Kevcel, 2 Apr 2008.

1. ### Kevcel

I've got a question, that actually isn't very important , but I'm just curious:

Does somebody know how the TDS wifi-rating is calculated?

2. ### Billmaan

To the best of my knowledge, nobody's sure. It seems ELO-like, but it's not true ELO. Regardless, reading up on ELO should probably give you the basic idea.

(If I'm totally off base, and we actually do know how it's calculated, I'd really like to know too.)

3. ### Rosti LFC

No, there was a lot of work put in to try and collect data and find out how it was calculated, but as far as I know, nobody (in the west at least, can't account for in Japan) figured it out.

There were a few points though that I remember:

1) It is not a zero-game system, ie. the points lost does not equal the points gained

2) If the higher rated player wins, more points are lost by the loser than are gained by the winner

3) If the lower rated player wins, more points are gained by the winner than lost by the loser

Really, though, being able to calculate the number of points isn't much of a big deal. The equation won't be that simple, or we'd have figured it out, and you generally know roughly how many points you'll win or lose from the games after a bit of experience on wifi. Knowing you'll gain exactly 22 isn't much different from knowing you'll gain "around 20".

4. ### tepplesLockjaw developer

Unless you want to make a simulator. That's why anybody has ever wanted to learn more about the TAP and Ti grading system than the "play faster and make more 4-line clears" stock advice.

5. ### ChaosUnregistered

Sorry for the thread bump, but a friend of mine came up with an interesting gauge of rating compared to skill of the CPU lvl in TDS, and I thought it would be best suited for this thread.

(7000 - 2000) / 1000 = CPU lvl.

So a 7000 rated player on Wifi would be roughly averaged to be a lvl 5 CPU opponent.

To me personally, it seemed to fall well from my own perspective of things, but then I gave it more thought, and began to wonder, that say you have an 8000 rated player. Would that be in fact an adequate gauge to call it that a lvl 6 CPU level? From what's seen from the jump from level 4 CPUs to level 5 CPUs, is someone like DIGITAL perhaps too hard for a level 6 CPU label? Or would it be fitting to say so? DIGITAL was my first and only thought as an example, only because his Blockstats siggy is the closest to 8000 lol. But personally I'd be piss angry if I had to go up against a CPU as good as DIGITAL just to beat what the would-be level 6 CPU.

Any thoughts suggestions to this equation?

6. ### Rosti LFC

I would say that the level 5 CPU is higher than a 7000 player. I've not played for a while, but against a 7000 player I'd expect to win maybe 80% or 90% of the games, if not more. I know for a fact I can't get a win ratio that high against the computer.

I'd estimate it more to be 7250-7500

7. ### Kevcel

First I must say that I'll forgive you, because the original discussion ended very fast, because nobody really knows the exact formula.
[But you could have easily opened a new topic, didn't you? ]

But I think I agree with Rost LFC;

Lvl. 5 CPU is stronger than a 7000 player.

So I disagree with your equation.

But I also think that a ''Lvl. 6 CPU'' would be playing fast and capable of using T-spins...a 8000 player normally match this description, so in this case I suggest that your equation is right.

8. ### Rosti LFC

Tetris Online Japan had a whole load of different CPU difficulties, with the top ones being pretty damn hard (I wasn't too great at it, but I couldn't beat quite a few).

It would have been nice if they'd done the same to Tetris DS.

9. ### tepplesLockjaw developer

How deep do you think a DS can search a game state tree, even using 50% of the 67 MHz CPU?

10. ### caffeine

You could get some videos of people at different ratings. See how much garbage they send per minute. Compare against the CPUs. I think that should roughly be a good guide to what each CPU is rated.

11. ### tepplesLockjaw developer

That's part of why Lockjaw calculates garbage per minute. But that stat isn't perfectly correlated with difficulty of facing a player, as the people who routinely kicked my butt on Blockstats were quick to point out. It's also a matter of how well a player can score tetrises and TSDs from garbage, so that the player can perform defense and offense at the same time.