In most claims that arise from accidents or injuries -- from car accidents to "slip and fall" cases -- the basis for holding a person or company legally responsible for any resulting harm comes from a theory called "negligence."

Generally speaking, when someone acts in a careless way and causes an injury to another person, under the legal principle of "negligence" the careless person will be legally liable for any resulting harm. This basis for assessing and determining fault is utilized in most disputes involving an accident or injury, during informal settlement talks and up through a trial in a personal injury lawsuit.

Specifically, in negligence claims the plaintiff (the person injured) tries to show that the defendant (the person supposedly at fault):

• Owed a legal duty of care to the plaintiff under the circumstances; and
• Failed to fulfill ("breached") that legal duty through conduct or action (this can include a failure to act); and
• Caused an accident or injury involving the plaintiff; and
• Harmed or injured the plaintiff as a result.

To illustrate how these four elements work, take a hypothetical personal injury case: Don speeds through an intersection against a red light and hits a vehicle driven by Pat, who had the green light and the right of way. In a personal injury dispute based on negligence, Plaintiff Pat will need to show that:

• As the operator of a car on public streets, Defendant Don owed all other drivers (including Plaintiff Pat) a legal duty to drive with reasonable caution under the circumstances; and
• By speeding through the intersection and running the red light, Defendant Don failed to fulfill ("breached") that legal duty; and
• In failing to fulfill his legal duty to drive with reasonable care under the circumstances, Defendant Don caused his vehicle to collide with Pat's car; and
• Due to his collision with Don's car, Pat suffered injury (property damage and physical injury)