What is the test for determining whether pre-trial delay violates the Sixth Amendment?

The determination of whether pre-trial delay violates the Sixth Amendment is governed by Barker v. Wingo, 407 U.S. 514, 530, 92 S.Ct. 2182, 33 L.Ed.2d 101 (1972), which identified four factors "courts should assess in determining whether a particular defendant has been deprived of his right[:] Length of delay, the reason for the delay, the defendant's assertion of his right, and prejudice to the defendant." Barker further instructed that the weight given to the individual factors must be evaluated on a case-by-case basis: