[the hog]

I would not rely on Wikipedia as a resource for anything. Have you actually played an unusual positive yourself? If the answer is "no", then you cannot comment sensibly. It is certainly playable, though as I have already said, and as mycroft says in his post above, it is not optimal.
By the way, a number of very good players still use it.

[straube]

The_Hog, on Oct 4 2010, 07:37 PM, said:

I would not rely on Wikipedia as a resource for anything. Have you actually played an unusual positive yourself? If the answer is "no", then you cannot  comment sensibly. It is certainly playable, though as I have already said, and as mycroft says in his post above, it is not optimal.
By the way, a number of very good players still use it.

I had a partnership that used a fairly standard version of Precision that did use the impossible negative and I've more recently played unusual positives. I didn't try to recommend the latter approach based on my experiences as much as provide reasons why unusual positives are imo better. One doesn't have to play every bad treatment to know that it's bad. I also mentioned the trend toward use of the unusual positives and that trend probably confirms that other people are deciding that unusual positives are better.

I'm glad you agree that impossible negatives are not optimal. I would go further and say that the impossible negative is unsound. Apparently it's just a difference of opinion.

[Mbodell]

gurgistan, on Oct 3 2010, 12:59 AM, said:

I have decided to learn precision and I am going to use this resource for my learning. Could someone just give it a quick once over and cofirm that it is a common enough form of precision for me to bother learning. I do not expect or want any detailed discussion of it. All I need is confirmation that it is a common enough understanding of precision for me to bother to learn.

If you already knew that link well and asked "could I play this system of precision and be mostly ok" the answer would be yes. If instead you ask "should I bother to learn it" the answer is not if you have any other choices (like learning from Berkowitz's precision today book).

If you just want to mess around with a partner and have both of you look at that web site you could get your feet wet, but it is not the best way to learn.