The Barker v. Wingo Test is a legal standard used to determine whether a defendant's right to a speedy trial has been violated, originating from the 1972 Supreme Court case Barker v. Wingo. This test outlines four factors that courts should consider: the length of the delay, the reason for the delay, the defendant's assertion of their right, and the prejudice suffered by the defendant due to the delay. These factors help ensure that defendants are not subjected to excessive delays that could impair their ability to mount a defense or harm their case.