Handcuffing the Cops: Miranda's Harmful Effects on Law Enforcement

Studies | Crime

No. 218
Saturday, August 01, 1998
by Paul G. Cassell


Crime Clearance Rates and Miranda

Figure III - Violent Crime Clearance Rate

"Clearance rates - the rates at which crimes are solved - are another way to measure the impact of Miranda."

The most meaningful alternative measure of the frequency of confessions is the clearance rate - the rate at which police officers "clear," or solve, crimes. Since at least 1950, the Federal Bureau of Investigation has collected clearance rate figures from around the country and reported this information annually in the Uniform Crime Reports.17 The clearance rate appears to be a reasonable (if understated) alternative measure for the confession rate. If Miranda prevents a confession, a crime may go unsolved. As one leading police interrogation manual explains, "Many criminal cases, even when investigated by the best qualified police departments, are capable of solution only by means of an admission or confession from the guilty individual or upon the basis of information obtained from the questioning of other criminal suspects."18

Clearance rates have been widely viewed - especially by defenders of the Miranda decision - as a statistic that would reveal its effects. For example, a widely cited passage in Professor Stephen Schulhofer's 1987 article praising Miranda reported the prevailing academic view that, while some studies suggested declining confession rates after the decision, within a "year or two" clearance "rates were thought to be returning to pre-Miranda levels."19 While an apparent consensus exists that clearance rates at least partially gauge Miranda's impact, one note of caution should be sounded. Police can record a crime as "cleared" when they have identified the perpetrator and placed him under arrest, even where the evidence is insufficient to indict or convict.20 As a result, clearance rates fail to capture any of Miranda's harmful effects if these show up only after a crime has been cleared. This means that clearance rates understate Miranda's effects.

"The number of violent crimes solved fell about 25 percent after Miranda."

The Decline in Clearance Rates. Surprisingly, no one has made a close examination of the national data from the FBI's Uniform Crime Reports. In a recently published article, Professor Richard Fowles and I showed that crime clearance rates fell sharply all over the country immediately after Miranda and remained at these lower levels over the next three decades.21 For example, in both 1966 and 1967 the FBI reported that a drop in clearance rates was "universally reported by all population groups and all geographic divisions."22 A long-term perspective on crime clearance rates comes from plotting the FBI's annual figures. Figure III illustrates the national crime clearance rate from 1950 to 1995 for violent crimes (nonnegligent homicide, forcible rape, aggravated assault and robbery).

Figure IV - Property Crime Clearance Rates

As the numbers show, violent crime clearance rates were fairly stable from 1950 to 1965, generally hovering at or above 60 percent. They even increased slightly from 1962 to 1965. Then, in the three years following Miranda, the rates fell dramatically - to 55 percent in 1966, 51 percent in 1967 and 47 percent in 1968. Violent crime clearance rates have hovered around 45 percent ever since-about 15 percentage points, or 25 percent, below the pre-Miranda rate. Because Miranda probably took effect over several years - while both police practices and suspect talkativeness adjusted to the new rules - simple visual observation of the long-term trends suggests that Miranda substantially harmed police efforts to solve violent crimes.

"The number of property crimes solved also fell."

The annual crime clearance rate during the same period for the property crimes of burglary, vehicle theft and larceny present the same pattern, as shown in Figure IV. The rate at which police cleared property crimes fluctuated somewhat from 1950 to 1960, declined from 1961 to 1965, then fell at an accelerating rate from 1966 to 1968 and generally stabilized thereafter. Here again, during the critical post-Miranda period, clearance rates dropped, although somewhat less dramatically than clearance rates for violent crime.

Did Miranda Cause the Decline? The graphs of crime clearance rates, particularly violent crime clearance rates, nicely fit the handcuffing-the-cops theory advanced by Miranda's critics and disprove the suggestion that there was any sort of "rebound" of clearance rates after the decision. Defenders of Miranda nonetheless might argue that this does not prove any causal link between the drop in clearance rates and the Supreme Court's new rules. The link, however, is strongly suggested by the striking timing of the sharp drop, originating in 1966 (and not earlier) and concluding in the year or two after. Moreover, it is important to recall that it was Miranda's defenders who first suggested exploring clearance rates as evidence of Miranda's effects.

The connection between the decline in clearance rates and Miranda was contemporaneously recognized. During the critical 1966-68 period, the Uniform Crime Report listed as explanatory causes for falling clearance rates "court decisions which have resulted in restrictions on police investigative and enforcement practices" along with "the sharp increase of police workloads in criminal and noncriminal matters; the almost static ratio of police strength to population, which is not commensurate with the sharp increase in crime; and the increasing mobility of those who commit crimes."23

"Most police chiefs believe Miranda raised obstacles to law enforcement."

Assessments from law enforcement officers who questioned suspects both while free from and subject to Miranda's constraints confirm the importance of Miranda in the drop in clearance rates. Perhaps the best interviews of officers on the streets were conducted by Otis Stephens and his colleagues in Knoxville, Tenn., and Macon, Ga., in 1969 and 1970. Virtually all the officers surveyed believed that Supreme Court decisions had adversely affected their work, and most blamed Miranda.24

Similarly, in New Haven, Conn., Yale students who observed interrogations during the summer of 1996 interviewed most of the detectives involved plus 25 more. They reported that "[t]he detectives unanimously believe [Miranda] will unjustifiably [help the suspect]."25 They also reported that "[t]he detectives continually told us that the decision would hurt their clearance rate and that they would therefore look inefficient."

Law student Gary L. Wolfstone sent letters in 1970 to police chiefs and prosecutors in each state and the District of Columbia. Most agreed that Miranda raised obstacles to law enforcement.26

In "Seaside City," James Witt interviewed forty-three police detectives some time before 1973. Witt reported that the detectives "were in almost complete agreement over the effect that the Miranda warnings were having on the outputs of formal interrogation. Most believed that they were getting many fewer confessions, admissions and statements ... [and] were quick to refer to a decline in their clearance rate when discussing problems emanating from the Miranda decision."27

While other social changes in the 1960s might have affected police performance, these changes were unlikely to account for the sharp 1966-68 drop in clearance rates. For example, although illegal drug use certainly increased during the 1960s, the increase continued into the 1970s and 1980s. Other social changes may have had some indirect effect on police effectiveness, but again such long-term changes are not strong candidates for an unexplained portion of the 1966-68 drop in clearance rates.

Finally, the conclusion that Miranda caused a significant part of the 1966-68 decline in clearance rates is supported by a wide range of information, and also by common sense. The conclusion suggested here is simply that when the Supreme Court imposed unprecedented restrictions on an important police investigative technique, the police became less effective. This is not a counterintuitive assertion, but instead a logical one.


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