In order to measure if Miranda impacts arrest/clearance rates, it is necessary to determine if police altered their investigative practices out of concern for how Miranda, standing alone, will affect use of confessions as evidence in trials. The realities of criminal prosecutions skew any attempts to isolate Miranda's effect.69 Following are four examples. Each involved a challenge to the use of the defendant's confession.
69 Beatty, G.D. (1999), The Allegory Of The Cave! (Statistical Studies of the Impact of the Miranda Decision on Law Enforcement). Criminal Law & Procedure Practice Group Newsletter ,Volume 3, Issue 2,