Ronny wrote an excellent article regarding the rareness of boards and the effectiveness of 3bv limits after Ians 33, and I propose we discuss his conclusion here.
For lazy readers, in the article 3BVO is defined as 3BV+2*(openings-1) to account for the fact that openings usually take more than one click to solve (except for the first one).
After statistical analysis, Ronny reaches the conclusion that expert boards with 3BV<100 are much rarer than intermediate boards with 3BV<30, and that the current 3BV limit on expert is not effective. This is because the 3BV distribution of expert highscores on the world ranking is hardly affected by the 3BV limit at all, and most expert highscore boards have a 3BV that is far above the limit, in contrast to intermediate, where most highscores have a 3BV that is close to the limit.
You really should read the article though: http://www.dmc-hq.nl/west_images/minesw ... _trial.pdf. Especially the last page or two.
My personal opinion is that we might want to consider ZiNi (http://minesweeper.info/forum/viewtopic.php?f=15&t=70) and do the same kind of analysis for that stat as well.
Apart from that I really do think that we need to change the limits, be 3BVO or 3BV (or something else) the stat we use.
That all said, once again, great job Ronny

