Phil Van Treese
Self defense, whether aikido, Gung Fu or what ever, is only as good as the person using it. What you put into it is what you will get out of it. As to "how effective is........." the answer is how good is the person using it?????
You could also suck at martial arts and self defense, but your opponent could be even worse and you still win. Or you could get a lucky shot in against a skilled adversary, and prevail that way. And the opposite could happen of course, and you could end up losing even when you shouldn't have lost. In those situations it doesn't matter how good you are. That mostly goes without saying.
The way I see it, everyone has a 50/50 chance in all combat situations, simply because of the unpredictable nature of combat and the uncontrollable variables that arise. But training, strength, and skill can certainly help you with your 50% of the equation. The other 50% you really can't do much about. It's fate and random chance at that point.