Tactics Trainer and the 60% barrier

Is anyone else curious why almost none of the Tactics Trainer problems have a pass rate of 60% or higher?

Although there are a handful of problems that do rate between 60% and 65%, it seems that the vast majority never break this barrier.

In all events, I have never yet seen a Tactics Trainer problem with a pass rate higher than 65%. If anyone spots one, please post a link to it on this forum thread!

My guess is that if your TT rating is too high, and you just aren't seeing the problems with higher pass rates, because they are too far below your own rating.

Hmm... I'm not convinced...

My rating on Tactics Trainer fluctuates between 1350 and 1750. Most of the problems I have seen (2,356 total, or 10% of the total collection) are rated around 1400 to 1500. But I have seen quite a few rated 1300 or lower, and some of those are really, really easy.

After doing so many problems, I would have expected to see at least a few with higher pass rates.

I am not saying this is a problem. I am just commenting on how bizarre it is that even the easiest pin/fork/checkmate problems never seem to break past the 60% or 65% pass rate.

If there is an easy way for somebody to scan the database, it would be interesting to know what the distribution of pass rates really is across all 22,039 problems...

Doesn't it indicate that the rating system of the tactics trainer is working?

The point of the rating system is to match a solver with the right level problem -- perhaps they should call it tactics harmony. What does it mean "the right level problem"? If all you get is problems you can already do, what are you going to learn? On the other hand, it is important to reinforce things you do know, so you should already know some of the problems. Also, some of the problems should be things you don't know, but can figure out over the board.

If you get every problem right, your rating goes up until you get some problems that you will miss -- and can learn new things from. If you get every problem wrong your rating will go down until you are on the edge of your ablity -- getting many problems right and some wrong. This seems like the right behavior to me.

The result is that tactics problems are being attempted by a good number of people who have something to learn from them. That is, the rating system is working.

Thanks to Baseballfan and Loomis. Your comments make sense.

I've noticed that as well. Now, allthough comments above make sense, I am thinking further. 

I have read how TT algorithm is built on Glicko rating system. Technically, you play a small timed match agaist the TT problem.

I could not find info on "match durata", how long does the match last, so I don't understand if "average time" is part of the algorithm. I also could not fint info on how  "percentaged success of achievment" is calculated. 

What I could conclude is that "passing rate" and "percentaged success of achievment", are not baked in the algorithm but are the mere consequence of the rating system.

Thereof, my observation, as yours, is that:

- 1 move problems tend to cluster on 55%-60% passing rate

-  Average time tends to cluster on 80% percentaged success. 

If you find where I read more about this stuff, pass the link.. thanks