I believe the thread's originator specifically said he needed something bigger than a 22 caliber, and wasn't inquiring about training, but about what is a suitable firearm for concealed carry. While a 22 can and will serve as a suitable concealed carry self defense weapon, within it's limitations, a 357 magnum loaded with a good 38 special is a much more effective and suitable, if not desirable choice, with the variables being consistently applied to both (such as level of expertise of the shooter, economics, etc).

Training is a separate issue altogether from what was requested. Although for what it's worth, I am a strong advocate of practice and the 22 is a most worthy, if not ideal, selection for the purpose.

If a full grown man can't hit a target with a good 38 cal revolver shooting a moderately loaded cartridge (the usual 38 special, non-plus p type for instance), then he most likely won't hit it with a comparable version in 22 cal either. Factoring out the necessary marksmanship requirements for either firearm or cartridge, which in my opinion are identical requirements for either to be considered effective, you are left with empirical evidence that a 38 special is going to be much more effective as a self defense round than any 22 lr.

In other words, a center mass hit from a 38 special at a given range is most likely going to have a much more desired effect on the opponent than will a 22 at the same range. There are going to be anomalous exceptions, to be certain, but for the most part, the bigger, heavier bullet at roughly the same velocity is going to do more damage and hit with greater force. A miss is a miss, regardless of caliber or bullet size, in the practical realm at least.

This, I believe is why the recommendations for bigger than 22 cal were offered, as it addressed the question more succinctly, which takes nothing away from Chris's point in the least. Good advice, whether solicited or not, is still good advice.