Harness versus collar for restraint

Question
If there is a dog that is aggressive around other dogs, is a collar or a harness more effective at insuring the pet remains restrained?  Is the dog more likely to "escape" a collar than a harness?

Answer
Either a martingale or a Prong collar are the best types of devices to use to ensure the dog won't get out,they can 'back out' of harnesses and slip out of flat collar and in some cases even chock chains

There's no way they can get out of either a Prong Collar or a Martingale and they tighten when a dog tries to 'back out' esp Prong Collars

Harnesses should be reserved for trained dogs only as it is VERY difficult to control a dog with a harness on