The U.S. Supreme Court's 1966 decision in Miranda v. Arizona created a series of procedural requirements that law enforcement officials must follow before questioning suspects in custody. These rules specified that a suspect must be read the "Miranda warning," now famous from police shows on television, and then must be asked whether he agrees to "waive" those rights. If the suspect declines, the police are required to stop all questioning. Even if the suspect waives his rights, at any time during an interrogation he can halt the process by retracting the waiver or asking for a lawyer. From that point on, the police are not allowed even to suggest that the suspect reconsider.

These requirements have had a substantial detrimental impact on law enforcement and the police have found it more difficult to get a confession. After the Miranda decision:

• The fraction of suspects questioned who confessed dropped from 49 percent to 14 percent in New York.

  
  

• In Pittsburgh, the confession rate fell from 48 percent to 29 percent.

• An estimate from the best available studies is that, across the country, confession rates fell by about 16 percentage points.

• Following the decision, the rates of violent crimes solved by police fell dramatically, from 60 percent or more to about 45 percent, where they have remained.

• The rates of property crimes solved by police also dropped.

With fewer confessions and fewer crimes solved, there were also fewer convictions.

• Given that a confession is needed to get a conviction in about one of every four cases, a rough estimate is that there are 3.8 percent fewer convictions every year because of Miranda.
• This means that each year there are 28,000 fewer convictions for violent crimes, 79,000 fewer for property crimes and 500,000 fewer for other crimes.

Defenders of Miranda also might argue that there is no causal link between the drop in crime clearance rates and the Supreme Court's new rules. However, when the percent of crimes solved (the clearance rate) is subjected to standard statistical techniques, with controls for other influences, the findings are that Miranda had a statistically significant effect on clearance rates for both violent and property crimes. Specifically:

• Between 8,000 and 36,000 more robberies would have been solved in 1995 in the absence of the Miranda ruling.

• Between 17,000 and 82,000 more burglaries, between 6,000 and 163,000 more larcenies and between 23,000 and 78,000 more vehicle thefts would have been solved.

• The ruling had a minimal impact on the solving of homicides, rapes and assaults.

Reasonable alternatives exist, and it is time to explore them fully. Other measures could be put in place to guard against coercive techniques to acquire a confession that at the same time allow police to obtain more confessions from criminals. For example, there could be a requirement that police officers videotape custodial interrogations, or that questioning take place before a magistrate. Alternatively, the courts could simply return to the historical "voluntariness" approach to the admissibility of confessions, where the court excludes confessions deemed "involuntary" because of physical force, threat of physical force or when factors such as the length of interrogation and the types of questions asked are considered.

In short, Miranda has, as its critics charge, "handcuffed the cops." It is time to consider removing these shackles and regulating police interrogation in less costly ways.