A case-control research design was used in this study with the aim of identifying the factors which differentiate solved and unsolved non-domestic homicides in Trinidad and Tobago for the seven year period 2008-2014. Two research questions guided the study:
1) Is the use of elements of a structured approach to investigate homicides associated with more solved cases?
2) Are certain characteristics of homicide cases associated with a higher likelihood of detection?
The data set for this study comprised all the non-domestic homicides reported to the Trinidad and Tobago Police Service from January 1st 2008 to December 31st 2014 was analyzed against 21 investigative variables and 16 solvability factors. Of these, only 2 investigative variables and 9 solvability factors were found to be strongly associated with solved cases. The two investigative variables were (a) 1st officer secured crime scene; and (b) investigator present at post-mortem. This study confirmed previous research findings in identifying the following variables as solvability factors (a) weapon recovered; (b) suspect named, (c) projectile recovered, (d) offender vehicle identified, (e) fingerprint found, (f) eye-witness (1vs. 0), (g) ballistic on weapon found, (h) 3 investigators versus 1, and (i) 4 investigators versus 1. The magnitude of these effects, measured with an odds-ratio meta-analysis suggested that the presence of these variables is positively associated with solved cases.
A model with three latent classes was found to best describe both the investigative variable and solvability factor variables. Based on the variation in the observed distribution, specifically the ratio of solved to unsolved cases, the classes were given the labels “Easy Cases”, “Normal Cases” and “Difficult Cases”. A similar variation was not observed in the detection status for the investigative variables – the proportions of solved to unsolved for each class were equally 50%. Consequently those results were discarded as they provided no useful insight into the homicide cases.
Table of Contents
1. Introduction
1.1 Overview
1.2 Why is this Study Important?
1.3 Thesis Outline
2. Literature Review
2.1 Introduction
2.2 Definition of Homicide Detection Rate
2.3 Homicide Detection Rates as a Measure of Performance
2.4 Measurement Issue about Detection Rates
2.5 Theoretical Frameworks on Homicide Detection
2.6 Reasons for Decline in Homicide Detection Rates
2.6.1 Changes in the nature of homicides
2.6.2 Changes in the nature of police resources
2.6.3 Changes in the Behavior of Witnesses
2.7 The Investigation of Homicide
2.8 Forensic Evidence in Homicide Investigations
2.9 Political Influence on Homicide Investigation
2.10 Case Characteristics and Solvability Factors
2.11 The Wellford and Cronin (1999) Study
2.12 Summary of Literature Review
3. Methods
3.1 Introduction
3.2 Research setting
3.3 Definitions
3.4 The Choice of Research Design
3.5 Data Sources
3.6 Data Extraction, Cleaning and Exclusion Rules
3.7 Data Limitations and Issues
3.8 Other Limitations of the Data
3.9 Selection of the Case Control
3.10 Investigative and Solvability Factors Checklists
3.11 Populating the Checklists
3.12 Data Analysis
3.13 Data Protection and Ethics
3.14 Summary
4. Results
4.1 Introduction
4.2 Description of the Data
4.3 Non-Domestic Homicides by Motive
4.4 Spatial Distribution
4.5 Average Geographic Detection Rates
4.6 Temporal Distribution
4.7 Homicide Victims by Ethnicity
4.8 Homicides by victims per homicide
4.9 Homicide by offenders per homicide
4.10 Homicide by Weapon Type
4.11 Frequency of Investigative Variables
4.12 Frequency of the Solvability Factors
4.13 META-ANALYSIS RESULTS
4.13.1 Investigative Variables
4.13.2 Forrest Plot of Investigative Variables
4.13.3 Solvability Factors
4.13.4 Forest Plot of Solvability Factors
4.13.5 Results of Latent Class Analysis
4.14 Summary of Results
5. Discussion
5.1 Introduction
5.2 INVESTIGATIVE VARIABLES
5.2.1 Positive Association
5.2.2 Negative Association
5.2.3 Uncertain
5.2.4 Overall Results
5.3 SOLVABILITY FACTORS
5.3.1 Positive Association
5.3.2 Negative Association
5.3.3 Uncertain
5.3.4 Latent Classes
5.3.5 Other Considerations
5.4 Implications
5.5 Recommendations for Future Research
5.6 Limitations of the study
5.7 Summary of Discussion
6. Conclusion
Research Objectives and Key Topics
The primary aim of this research is to identify the factors that differentiate solved from unsolved non-domestic homicides in Trinidad and Tobago during the 2008-2014 period. The study investigates two main research questions: whether structured investigative approaches are associated with higher case resolution and if specific homicide characteristics correlate with an increased likelihood of detection.
- Application of a case-control research design to homicide data.
- Meta-analysis of 21 investigative variables and 16 solvability factors.
- Utilization of Latent Class Analysis to categorize homicide investigation outcomes.
- Evaluation of police performance and the impact of evidence-based investigative practices.
Extract from the Book
The Investigation of Homicide
While homicides per se have been the subject of many researches, the mode of investigation has not (Keppel and Weis, 1994). Much of the information on investigating homicides is based more on anecdotal evidence handed down by word of mouth (Keppel and Weis, 1994). Most text books devoted to homicide investigations relies heavily on the subjective experience of their respective authors. The paucity of confirmed knowledge in this area is not surprising since police investigations is an area which academics and criminologists have traditionally neglected (Keppel and Weis, 1994).
In a more recent study, Keel et al (2009) suggested that insufficient academic work has gone into determining law enforcement best practices that provide substantive insights for solving homicides. Most of the empirical work in this area has focused more on responses by the criminal justice system to homicide (e.g. Jarvis and Regeoczi, 2007; Roberts, 2007; Litwin and Xu, 2007; Alderden and Lavery, 2007).
Some researchers have associated the skills possessed by detectives coupled with their experience (length of years on the job) with homicide detection (Marche, 1994; Keel et al., 2009). Greenwood et al (1977) argued that an investigator’s experience is unrelated to homicide detection but asserted that detective caseload and the quality of homicide investigations do influence detection rates (i.e. as detective caseload increases, probability of detection decreases).
Summary of Chapters
Introduction: This chapter establishes the importance of the study, focusing on the high homicide rates in Trinidad and Tobago and the necessity of improved detection for deterrence.
Literature Review: This section explores existing research on homicide detection rates, investigative processes, and the role of forensic evidence and solvability factors.
Methods: This chapter outlines the case-control research design, data extraction processes from police databases, and the analytical techniques including meta-analysis and Latent Class Analysis.
Results: The chapter presents findings on non-domestic homicides, including spatial and temporal distributions, and identifies the predictive power of various investigative variables and solvability factors.
Discussion: This section interprets the study's results in the context of policing practices, addressing why certain variables associated with solved cases in previous studies did not perform as expected locally.
Conclusion: This final chapter synthesizes the main findings, reiterates the importance of evidence-based investigative practices, and offers recommendations for future criminological research.
Keywords
Non-domestic homicides, case-control research design, odds ratio meta-analysis, latent class analysis, investigative variables, solvability factors, homicide detection rate, Trinidad and Tobago, police performance, forensic evidence, witness cooperation, criminal investigation, police legitimacy, evidence-based policing, crime scene management.
Frequently Asked Questions
What is the core focus of this research study?
The study focuses on identifying the specific factors that differentiate between solved and unsolved non-domestic homicide cases within the jurisdiction of Trinidad and Tobago from 2008 to 2014.
What are the central themes examined in this work?
The central themes include homicide detection rates, the standard of the homicide investigation process, and the identification of empirical solvability factors that assist in solving cases.
What is the primary research objective?
The primary objective is to determine if adopting structured investigative approaches and focusing on identified solvability factors can improve the low homicide detection rates observed in Trinidad and Tobago.
Which methodology was employed to analyze the homicide data?
The researcher utilized a retrospective case-control study design, performing an odds ratio meta-analysis and Latent Class Analysis on 200 selected cases to determine the influence of various variables.
What topics are covered in the main body of the thesis?
The main body covers the theoretical frameworks of homicide detection, the impact of police resources, the role of forensic evidence, and an analysis of how specific investigative actions and case characteristics affect case outcomes.
Which keywords best characterize this study?
Key terms include Non-domestic homicides, case-control research design, odds ratio meta-analysis, latent class analysis, investigative variables, and solvability factors.
Why was the case-control research design considered most appropriate?
The design was chosen because it is powerful and efficient for retrospective research, allowing for the comparison of two groups (solved vs. unsolved) to identify predictive attributes that differentiate their outcomes.
What was the role of the Wellford and Cronin (1999) study?
The Wellford and Cronin study served as the empirical foundation for this thesis, providing the conceptual framework and a set of investigative variables and solvability factors used to analyze the Trinidad and Tobago data.
What significance do the identified 'latent classes' hold?
The three identified latent classes—"Easy," "Normal," and "Difficult"—provide a novel way for police decision-makers to categorize cases and predetermine the resource requirements needed for an optimal investigation.
- Quote paper
- Andre Norton (Author), 2015, A Case Control Study of Non-Domestic Solved and Un-Solved Homicides in Trinidad and Tobago, Munich, GRIN Verlag, https://www.grin.com/document/319951
