Is aikido an effective martial-arts?
If you rely on pure aikido, then it is totally ineffective. Aikido can be only helpful tool. Let me explain what I mean by this.
Many aikido practitioners are in general very skinny. They are very soft. They are not intense. They dont have any experience in any other martial-arts. If they get involved in a fight, they will get smashed.
In order to change that, they need to start lifting weights, get some muscle, get some mass, some strength, and they need to learn how to box, strike, kick, punch, learn how to wrestle… and only then their aikido can be effective.
Many aikido moves can do real harm to opponents. If you know how to perform them, sure, it can be very effective. But real fight is unpredictable. To rely only on aikido, I am certain 100% that you will lose the fight. Dont focus on aikido. Fight back. Kick, punch, take them down on the ground, have some strength, be intense, be tough. And if you get a chance to do any your aikido moves, then do it. Rip out their arm. Do your magic.
But thinking that you will take few aikido classes and you will be able to protect yourself is complete non-sense. Practicing aikido only is totally unpractical. It is beautiful martial-art, I have to admit. It is very gracious. It can be fun, it can be easy workout, it can be entertaining, you can meet a lots of people, it can be good for kids, good for older people, good for people that are not in shape, good for people that are recovering from something… But you cannot expect that you will train ballet and be able to kick someone’s ass.