What is the criteria for choosing a really good lawyer?

Win-loss records are the least meaningful way of choosing a lawyer. Any lawyer can avoid "losing" by settling all his cases & claiming victory (That's how D.A.'s get those 90% conviction rates) or by refusing difficult cases that can be lost. Moreover, in most cases only an insider knows whether it is won or lost. ie. A personal injury case with a million dollar demand by Plaintiff & a settlement offer of $250,000 by defense; where after a trial, the jury verdict is only $100,000. That's technically a victory for the Plaintiff, but in reality it is a big victory for the defense. If you don't know what the offer & demand were you'd have no idea.

In my view the best criteria are the references of other attorneys & judges. I find that in general, attorney's & judge's accurately evaluate their contemporaries when making referrals. The next best are referrals from former clients. Clients tend to be impressed by outcomes, but they also have experience of face to face dealing with attorneys & know how approachable they are, how responsive to client concerns & whether they believe they've ben over-billed.

You can. Such statistics are available, usually for a price.

But the biggest criteria I'd use are based on successful experience, not just specialization on paper, and how well I get along personally.

Becuase if I cannot communicate comfortable and freely with my attorney, then all the credentials in the world won't make them effectve in my particular case.

search the web for how many cases he's won verses how many he's lost. you should get information or find out where to check. also maybe call the state bar in your area to find out

You research