What is the effect of a retroactive statute on the conduct of trials?

A statute is applied retroactively only if it changes the legal consequences of an act completed before the effective date of the statute. A statute addressing procedures to be utilized in legal proceedings not yet concluded operates prospectively for acts to be performed after the effective date of the statute. The concept is explained in Tapia v. Superior Court (1991) 53 Cal.3d 282, 288: "Even though applied to the prosecution of a crime committed before the law's effective date, a law addressing the conduct of trials still addresses conduct in the future. This is a principle that courts in this state have consistently recognized. Such a statute 'is not made retroactive merely because it draws upon facts existing prior to its enactment. . . . [Instead,] [t]he effect of such statutes is actually prospective in nature since they relate to the procedure to be followed in the future.' [Citations.]"