Forum Ideachess

Improved text for FAQ.

The player and the problem are considered as opponents and both have their rating adjusted after each solution is attempted. If the player fails to solve the problem their ELO is lowered and the problem ELO is raised and vice versa. The amount the ELO changes depends on the ELO difference between the two and the RD parameter. RD stands for Rating Deviation and measures the accuracy of a player's rating; the lower the Rating Deviation the more accurate the rating. When a new player registers on ideachess their rating is set to 1500 and their RD to 350. It's about the same when a new problem is added on the ideachess database.

The best line is found using the open source chess engine Stockfish with 20 sec thinking time. The internal chess engine that evaluates alternative solutions is much weaker but it's optimized for tactical positions; it's ELO rating is over 2000.


Note!! evaluates

Only active players are shown in the tactics ranking.
A player is considered active if they have attempted at least 10 ELO tactics problems in the last 30 days. The active status is not updated in real time, because it is computational heavy, it is upgraded once every few days. I do it manually with a store procedure.

The puzzles with very low votes will be removed after some time on statistical basis, so the average quality of the problems will rise.
The "Average rating" of the stars is about the quality of the problem and NOT the difficulty of the problem!

Note
a statistical basis

I can't force the chess engine to accept a specific solution, all is done automatically. Give the problem a low quality rating, 1 or 2 stars, and it will be removed as soon as it has a statistically significant number of votes.

Do the problems get harder as the player's rating gets higher?

Yes, problems are assigned to you according to your ELO. For tactical problems an ELO is choosen between your ELO and your ELO-400 points.
Remember that newly added problems have an inaccurate ELO rating. The problem RD value indicate how accurate it is. With more attempts by the players to solve the problem its RD will lower and the problem's ELO will become more accurate.

Almost all the problems come from real games. Every week I analize the Week In Chess PGN files to find interesting tactical positions from the major world wide chess tournaments.
For more than 2 years I have had at least one computer, and often more than one, running software written by me analizing games 24 hours a day for 7 days a week!

Changes made. Thak you DATR!

Is average-time calculated on the correct answers or all?

I'm trying to understand if I'm slow or many people attempt to answer in 30 seconds.

PS: I apologize about my eng