This means that a defendant is liable for committing the action and it does not matter what his mental state was nor what he intended to do when he committed the action. Easy examples are possession of narcotics (you have them, it doesn't matter what you were going to do with them, you're liable) or statutory rape (it doesn't matter if she said she was 18, if she showed a (fake) ID, etc., if you sleep with someone underage, you're liable).
This is failing to behave with a level of care that a reasonable person would have behaved with under the same conditions. In order to prevail on negligence claim, one must establish four elements:
- the existence of a legal duty from the other person to you
- the other person's breach of that duty
- you having suffered an injury
- proof that the breach of that legal duty was the cause of that injury
While usually this has to do with actions taken (e.g., you negligently sped your car out of a parking lot...) in situations where there is a duty to act, even an omission can suffice.
Strict Liability and Negligence are both standards are liability. Put simply, negligence law requires a defendant to pay for the harms done by their unreasonable activity; strict liability requires a defendant to pay for all harms caused by their activity, regardless of whether the activity was reasonable or unreasonable.
Res Ipsa Loquitur doesn't apply to strict liability. Strict liability is strictly the simple formulation described above: you did it, it's on you. None of your "But-buts..." or proclamations of "I was misled!" are going to get you off the hook.
Res Ipsa Loquitur is Latin for "the thing speaks for itself." Basically, it allows a Plaintiff to create a rebuttable presumption of negligence by the defendant by proving three things:
- The thing that happened was the type of thing that generally doesn't happen without negligence.
- It was caused by something solely under control of the defendant.
- The plaintiff did not contribute to causing that thing that happened.
Difference in Final Compensation
This is hard to answer because of the types of cases usually found applying each. Strict liability is usually seen in criminal law in the ways described above and in tort law in specific circumstances... One is owning an abnormally dangerous animal and another is conducting abnormally dangerous activities. The dangerous animal concept is why pitbill owners don't want the breed classified as a "dangerous breed."
Nonetheless, though, here's a Harvard article actually comparing compensation in strict liability vs. negligence lawsuits!
I hope this helps.