Clearance and Crime Rates Unaffected by Changes in Detective Work
The FBI Uniform Crime Reports for 2001 indicated that the clearance rate for homicides was 65% (Richardson and Kosa 1). The clearance rates for other types of crimes -- such as assault, theft, or rape -- were all much lower than this. For the uninitiated, clearance rate refers to the rate at which police departments are able to gather sufficient evidence to charge and arrest an individual. Clearance rates are not the same as conviction rates, nor do they necessarily imply a one-to-one correlation with crime rates. Nonetheless, increasing clearance rates is generally perceived to be a good thing, primarily because it means that police are solving a greater number of crimes. The arrested suspects might not be convicted -- for unrelated reasons -- but offenders certainly face no danger of conviction if the police cannot even clear their case in the first place. Thus, understanding the factors that can affect clearance rates in police departments is a crucial component of the police's role in maintaining order and punishing offenders for crimes.
With clearance rates as low as the figures that have been cited by the FBI, it might seem surprising that police are able to clear any crimes. but, in fact, an examination of the way in which police work is done reveals that very specific aspects of police work affect clearance rates. Surprisingly, changes in detective procedures or resources are not a significant factor in affecting clearance rates for crimes. Within the bureaucracy of most police departments, detectives are the group of officers who are assigned with the task of clearing new crimes that are perpetrated within their new jurisdiction. Crimes are assigned to detectives who, according to the movies anyway, doggedly pursue suspects, amass hidden evidence, and then make brilliant leaps of deduction in order to put away a killer or catch a psychopath. As a result of this image of police work, the natural impulse had to combat low clearance rates is to simply get more detectives on the job, or else change some aspects of detective work in order to make them more efficient at their jobs. Unfortunately, detectives rarely behave like those we see on television or in the movies. Instead of being hired for their Holmes-like reasoning abilities, detectives are more often promoted to become "consummate bureaucrats" whose primary task is to triage cases, read reports, complete paperwork, hold meetings, and discussing general policing procedure (O'Connor).
A survey of the available literature and research on the subject, particularly the oft-cited RAND report from 1975, reveals that no increases in the number of detectives on the job or other changes in detective work will have an appreciable impact on the clearance rates of police departments. Similarly, as we shall see, clearance rates are not positively associated with crime rates -- thus changes in detective work will not have a significant effect there either. Though commonsense tells us that more police, in this case more detectives, will increase the effectiveness of the police to clear cases and reduce crime, the evidence does not support this tenet. Instead, we must accept the reality that more detectives or other changes to detective work will not raise clearance rates or lower crime rates.
Clearance rates in the United States, according to the statistics on the issue, are less then the public, politicians, or even the police would like. The highest clearance rates are for murder cases, though the FBI reports that even the clearance rate for murder is still less than 70% (Livingston). Some sources place the rate as low as 60% for homicides (Christianson). Unfortunately for the general state of crime clearance in the United States, these are the highest rates of case clearance reported. When we consider other types of crimes, the rates of clearance are significantly lower than this. In the mid-1990s, the clearance rate for robberies was an abysmal 25%, while the clearance rate for burglary or theft cases was even lower at less then 20% (Livingston). By the start of the 20th century, the clearance rates in the nation had plummeted even lower, following trends that had been occurring for the previous twenty years. Homicide clearance rates of 60% today contrast terribly with 90% clearance fifty years ago. Today rape cases clear at the rate of 42%, robberies at 26%, and burglary at 13%. Between 1980 and 1996, the national homicide clearance rate alone plummeted 7% (Wellford and Cronin 3; Christianson). These falling rates seemed to indicate that not enough resources are being allocated to the task of solving the cases that face the police, or that the available resources are being grossly mismanaged.
What makes the situation even more confusing is that while crime rates nationally in the United States have been falling over the last decade, clearance rates are at the lowest levels ever (Christianson). The obvious implication of this statistical reality is that clearance rates do not necessarily have a positive effect on crime rates. This is not to say that they will have a negative effect, but if there was a one-to-one relationship between the two, then we should expect to see crime rates go up when clearance rates go down. Because this is not born out by the evidence, we can rightly assume that increasing the clearance rate will not decrease the crime rate. The crime rate in the United States has been steadily dropping over the last decade despite the fact that clearance rates are at their lowest levels ever. The conclusion we can draw from this is obvious: manipulating clearance rates will not have an appreciable effect on crime rates.
But this conclusion should be fairly obvious, even without resorting to historical evidence. Clearance rates are indicators of how able police departments are at effectively solving crimes that have already occurred. In order to raise clearance rates (a good thing) it is necessary to solve more cases. Crime rates, however, are indicative of how much crime is being committed. In order to reduce crime rates (usually considered a good thing), it is necessary to enact preventative measures that prevent crime from occurring in the first place. Solving a preexisting crime will have no effect on crimes that are yet to occur -- unless one were to argue that clearing an existing case would prevent that criminal from committing another crime. That, however, is a dubious assumption at best not at all supported by the fact that clearance rates have been decreasing even as the crime rates in the country have been too.
Having established that crime rates will not be appreciably affected by clearance rates, we are still left with the matter of diminishing clearance rates in the United States and what to do about them. Obviously, if clearance rates are still falling -- as they are -- it means that of the crimes that are being committed, criminals have an increasing chance of getting away with them without being caught by the police. In order to understand the factors that have been affecting the low clearance rates -- and why more detectives will not improve the situation -- we must consider the role that detectives play in clearing cases, some relevant studies, and why cases end up being cleared in the end. The role of detectives within the police department is simple: investigate and clear crimes. To accomplish this task, detectives are usually given a general knowledge of the skills that will be needed to solve cases, such as forensics or criminal profiling. In some larger police departments, detectives might be granted specialized training in one or two types of crimes in order to increase their effectiveness. Detectives are armed with a basic knowledge of how to secure evidence and synthesize it in order to solve and clear cases (Purpura 167).
Unfortunately for the ego of detectives everywhere, the primary action detectives find themselves tasked with is not breaking down doors or deducing the whereabouts of a kidnapped victim, but rather filling out and processing paperwork. It has been estimated that nearly 80% of the crimes that are cleared in the average national police department are due entirely to the initial hard work of patrol officers who compile evidence and gather witness statements. Credit is given to detectives for solving these crimes when they synthesize the information gathered into a single file and then make an arrest (O'Connor). In general, it would seem that cases are not cleared because detectives are especially brilliant, trained effectively, or there were enough of them but instead because witnesses were available at the scene to tell detectives who committed the crime (Livingston). This conclusion might seem unpalatable to those of us who were raised on cop dramas or idolized police heroes, and may sound downright insulting to actual police detectives, but it is nonetheless supported by numerous studies on the subject.
The Rand Corporation conducted one of the most comprehensive studies to first come to this conclusion in…