The Factors That Affect Britain's Homicide Clearance Rate

This project examines the method of policing agencies in solving homicides in England and Wales. Moreover, I will go into depth about the factors affecting the national homicide clearance rate in England and Wales. Four key points will be analysed using both primary data collected from a survey of various agencies across England and Wales, as well as secondary data gathered from reliable online sources. These include, briefly, the management of practices, investigative procedures, analytical methods and demographics of the general public affected, and the overall effect these have on the agency’s ability to clear a homicide case. Evidently, the results suggest that there are certain factors that play a bigger part than others.

Foreword

Though murder and homicide are considered to be different (homicide is defined as “the killing of one person by another”, whereas murder is simply a homicide committed with “malice aforethought”) for the sake of this project they will be one and the same. I wanted to research what the current statistics are in terms of homicides being committed in the UK, and the trend between the amount of homicides being committed to the rate of crime clearance. Subsequently, I wanted to deliberate on why the trends are the way they are – if clearance was lower than the rate of crime, why is this? What affects homicide clearance rate? It should also be noted that some of the collected secondary data sources are based on data from the USA, however, the procedures for homicide clearance in the UK and the USA are almost interchangeable; i.e. with very few and minute differences.

The solving and subsequent clearance of homicide cases is obviously of the utmost importance for police departments and the communities they protect. Unfortunately, the national clearance rate for homicide in England and Wales has dropped significantly in a very short amount of time – with a decrease of roughly 47% of homicide cases being cleared from an original 77% clearance in Apr ‘06 - Mar ‘07, leading to just a minuscule 30% clearance rate in Apr ‘16 - Mar ‘17, according to the data in the Home Office Homicide Index. This is a shocking figure, but coincides with what BBC News reports: that “only 9% of crimes end with suspects being charged”, and that “nearly half (48%) of investigations are closed”. This raises questions as to why only roughly 3 in 10 homicides were solved in the most recent data provided by the Home Office Homicide Index (Apr ‘16 - Mar ‘17). In a recent article, BBC News reports that the number of homicides being committed has “risen for a fourth year”, which subsequently insinuates that the charge and clearance rate for homicide cases will only decrease further. For example, from the aforementioned Home Office Homicide Index, I have created a graph that shows the trend of homicides left uncleared against number of crimes being committed annually.

Here we can see that there is a direct correlation with the number of offences and the clearance rate. From the graph it is even more evident that homicide numbers are increasing, and thereby the homicide rate in the UK is at an all-time high. Furthermore, the solve rate is incredibly low, and can be seen to be increasing rapidly, which solidifies BBC News’ statement. Popular news reporters such as The Independent (2018) and The Guardian (2018) have both written similar articles that homicide rate will only continue to increase, and that there is little chance of returning to the high homicide clearance range from 13 years ago. BBC News has further reported that with the correct funding, investigative procedures, adequate staffing, and better analytical processes many more homicide cases could be responded to and cleared effectively. This conclusion is not strictly incorrect; however, it is unreasonable to say that every homicide case can be solved; many crime scenes have insufficient evidence or are simply discovered too late and subsequently have lost evidence to time.

For example, the case of the Jamison family will likely never be solved as the crime scene was left undiscovered for a prolonged period and was therefore tampered with by animals and general decay – there was not enough evidence to further the investigation. Furthermore, it should also be considered that crime scenes are rarely orderly, and it is often hard to trek through a timeline in order to create a profile of the offender. These issues aside, the question remains as to why the homicide clearance rate is so low, and whether the police processes that support homicide investigations can be improved.

Source Availability and Previous Data

Even though homicide clearance is presumably a big issue, and ways of making this rate higher must surely be a persistent practical question in law enforcement, there are few sources available to produce substantive insights into the best practices for police agencies to solve homicides quickly and efficiently. There are a few texts that delve into the criminal justice responses to homicide (mainly in the USA) but they are somewhat outdated, and I have found none that relate specifically to the UK: for example, Alderden & Lavery, 2007; Mouzos & Muller, 2001; etc. These texts, however, do not really provide much clarity as to the impact of resources and management, procedures, processes, or demographic influences on the rate of homicide clearance. However, there are certain sources that go into small detail about it, and these are summarised below.

Management and Resources

It is more than likely that case clearance is affected by the resources available to investigate them. In contrast, some have suggested that these factors have little to no impact on the outcome. More recently, Brookman & Lloyd-Evans (2015) have stated that insufficient resources can negatively impact the time taken to solve a homicide case, implying that the clearance rate is lower due to a lack of resources in the homicide department. Furthermore, this essay further acknowledges that there are other factors affecting case clearance but points out that one of the main reasons would be lack of resources. An example of further factors can be found in the work of Wellford and Cronin (1999), which hints that police response times and the number of investigators available are important variables for understanding clearance rate. Although these are both organisational and operational factors, they are also a function of the personnel and other resources a police service may have available to respond to reported homicides.

Investigative Procedures

It goes without saying that the performance of homicide detectives would have a direct correlation with the effectiveness of homicide clearances. Most of the sources have indicated that, practically, investigative procedures matter the most, however there are some procedures that may work better than others. In the work of Geberth (2016), it is stated that the main factors that affect investigative procedures include, but are not limited to, witness availability (“Homicides, especially those without witnesses, are extremely difficult to solve”), the relationship between the victim and the offender, investigator experience and volume of cases, weapon use, as well as circumstances and motives. These factors are often mentioned in the works of others too, namely Wellford and Cronin (2000), Reiss (1971), Litwin & Xu (2007), as well as many others.

Analytical Processes

Recently, the availability and use of analytical procedures to assist the examination of case information has been an area that is increasingly considered. Although it can be argued that analytical processes can be linked to investigative procedure, this area is more focused on the use of technology, tools and methods for supporting investigative decision making. Crime analytic technologies and methods are typical of this discussion. Forensic tools such as DNA collection and analysis, blood spatter analysis, ballistics, and other such tools are commonly available to each forensic department, however there have been cases where these samples have been tampered with, or lost, or otherwise. No sources mention whether these technologies are used in every case, or which method is more successful.

Contextual and Demographic Factors

The role of demographics in homicide is also a common area of examination when studying police approaches to homicide investigation and is therefore an important factor in homicide clearance rates. Some sources, namely Black (1976, 1980), have noted that police devalue victims of certain demographics when investigating criminal complaints. In terms of homicide clearance, this is often expressed as victims from lower social classes receiving less clearances that those of higher social classes. Contrastingly, Puckett & Lundman (2003) state that “victim social class have no effect on homicide clearance”. These contrasting views seem to highlight the incongruous nature of homicide investigation, and the lack of information available seems to show that there is little work being done to improve that. Other possibly influential factors on homicide clearance are considered to be size of the department, the size of the population being served, the number of officers on hand to work on the homicide investigation and the region of the country.

Data and Method

Before applying my own specification of how murder clearances are measured, it must first be acknowledged that there have been other ways of measuring the rate. Depending on the convention followed for calculating such rates, these metrics may be important for understanding variances in both reported rates and the variation found in the few previous studies that use such measures.

Measuring Homicide Clearance

The definition of crime clearances as stated by the FBI in crime reports details that an offense is “cleared by the arrest or solved for the crime reporting purposes when at least one person is arrested, charged with the offense, and turned over to the court for prosecution” (FBI, 1984, p.41). Although this definition seems clear and has been used for a very long time (since about 1930), other metrics are sometimes used. For example, some cases are unable to meet this definition but are oftentimes considered to be exceptionally cleared when circumstances such as the death of an offender occur, for example.

The competency of managing cases in this way aside, some agencies may exclude these types of cases when producing their reports on clearances for any given year, which further complicates the situation as the results may not all be on the same criteria and thus may not be reliable. Furthermore, homicides sometimes take long periods of time to solve, and therefore may be solved years after they are actually committed – this means that the data for any given year may be changing constantly. Therefore, homicide clearances are often measured as the amount of crimes that are solved that year, as opposed to how many of the committed crimes in any given year are solved (which will be referred to as the current year clearance rate from here). This is the measure that will be used in this study as is detailed further on.

Study Data

Measurement issues notwithstanding, this project was collected from a survey sent to 44 different policing agencies across England and Wales based on set selection criteria, namely that the agency must deal with, or have experience in, homicide investigation. Therefore, the agencies must have experience with an average of 15 homicides or more per year for the 5-year period 2012-2018.

The survey protocol consisted of 103 questions covering many distinct categories thought to influence the effectiveness of investigation. These included homicide detective selection processes, investigative procedures used, witness processing, management of case assignments, resource use, medico-legal issues, other administrative aspects, training, crime lab issues, and prosecutorial issues. In addition to these specific areas, every responding agency was asked to report their number of homicides, current clearance rates, number of prior year homicide clearances, and staffing number for the past 5 years. Of the 44 agencies that met the criteria, 26, yielding a response rate of 59.1%, which I think is a suitable response rate for this particular survey.

Dependent Variable

Informed by the sources previously reviewed, the independent variables were collected from the survey responses and compiled into the following four dimensions:

1. Staffing and Management. This dimension grew on the variables measuring aspects of the department’s day-to-day operations such as caseload, number of responders to homicide calls, overtime utilization policy, rotation policy for assignments, and the existence of cold case squads.
2. Investigative Procedure. Again drawing on researched sources, this dimension relied on variables in the survey relating to procedures commonly used in the investigative processes and procedures of homicide detectives. This includes formal interviews of potential suspects and the victim(s) friends or family, whether a system is in place for follow-up investigations, and the number of detectives initially assigned to work a case.
3. Demographics. Previous studies are quite ambiguous when it comes to examining the influence of demographic factors on the solvability of homicide. Variables reflecting this dimension included jurisdictional population, volume of homicides, clearance for crimes other than murder, and population density.
4. Analytical Practices. Accessibility and use of investigative tools such as a polygraph, criminal investigative analysis, computer voice stress analysis, bloodstain pattern analysis, and statement analysis clearly could improve the chances of solving a case. By including questions concerning these practices on the survey, measurement of this dimension was possible. Other practices or capabilities used in constructing this dimension included the following: whether a department has a computing capability to flag witnesses in previous cases, whether they used a computerised case-management system, use of proactive crime analysis, use of crime analysis reports for homicide areas, videotaping crime scenes, and access to a well-established DNA database.

Analytical Strategy

Reponses yielded 26 useable surveys. A subset of the 103 survey items was useful for constructing indicators as suggested by the previously mentioned sources. Using the previous work as a guide, four main scales were derived by employing Cronbach’s alpha reliability analysis to determine linear combinations of variables that would reflect the key dimensions of management, investigative procedures, and analytical processes that may affect homicide clearance rates. Demographic impacts were not scaled but allowed to be explicitly examined because these are often in varying metrics. The resulting alpha coefficients suggest adequate reliability and consistency for combining these items to construct additive scales for later analysis. First, however, descriptive statistics for all variables included in the analysis is examined to detect any apparent relationships with the homicide clearance rates. These results are then used to construct a multivariate regression model using any relationships noted and the derived scales reflecting the key dimensions to be examined.