SUPPORTING EVIDENCE-BASED PRACTICES FOR VIOLENT CRIME INVESTIGATIONS

Overview

Nonfatal shooting incidents are a severe form of violence that involve an offender intentionally pointing and discharging a firearm at a victim and striking them with the projectile. Little differentiates these acts from fatal shootings, yet U.S. police departments often direct greater effort and resources toward solving homicides than they direct toward solving nonfatal shootings. Police departments experience high rates of nonfatal shootings, especially in medium-to-large sized cities, yet frequently do not have the staff or resources sufficient to prioritize these investigations. To compensate, agencies often triage nonfatal shooting cases based on how likely the case is to result in an arrest and conviction (i.e., how "solvable" the case is), with the goal of optimizing justice and public safety in the context of limited resources. How staff determine which cases have higher solvability can vary by agency, and by person; thus making the solvability determination informal, inconsistent, without transparency, and potentially inaccurate. To address this issue, the National Case Closed Project developed a solvability calculator to be used in active nonfatal shooting investigations that should improve accuracy, uniformity, and transparency in case solvability triage decision-making.

Methodology

To develop this tool, we first conducted a review of scientific research on the factors that predict case clearance in incidents of severe violence, which typically involved homicide cases. We documented the frequency of findings across studies as well as the magnitude of the relationships between the solvability factors and the likelihood of case clearance. After using this research to develop an initial list of solvability factors, assigning solvability scores to each, and assigning solvability rankings to total case solvability scores, we asked experienced violent crime investigators and researchers who study investigations to review this information and provide feedback.Their feedback, which was minimal, was incorporated into the solvability calculator to produce version 1 of the National Case Closed Project's nonfatal shooting solvability calculator.

Importantly, although this calculator is based on scientific evidence and expert opinion, it has not been formally evaluated. Therefore, the National Case Closed Project considers the calculator preliminary, and requests that law enforcement agencies who choose to use the calculator evaluate it—both in terms of how accurately it predicts nonfatal shooting case solvability and how well it works to avoid unintended consequences in case triaging such as the unfair distribution of investigative resources—and provide feedback to the National Case Closed Project so that we may work to improve the tool.

Important Considerations

The National Case Closed Project intends for its solvability calculator to be used as a supplement and not a replacement to conducting a thorough investigation. In other words, all active leads in a shooting investigation should be exhaustively investigated, regardless of how solvable the case appears. Once all leads have been investigated and case momentum has begun to stall, the tool can be used to supplement an investigation by providing guidance to lead investigators and their supervisors about 1) the solvability of the case, and 2) the amount of time and resources to dedicate to developing new leads. See National Case Closed Project: Core Standards for Fatal and Non-fatal Shooting Investigations.

The User Guide provides a more detailed description of the tool including how it was developed, its intended use, and limitations and considerations in using the tool. It also provides instructions for using the tool and interpreting its results. The User Guide can be downloaded below.

Solvability Tool in Action

The figure below provides an example of how a law enforcement agency might utilize the solvability calculator to determine the resources available for an active nonfatal shooting investigation. Step 1 involves documenting case facts relevant to the solvability calculator during the initial response. Note that some departments may choose not to apply the calculator in certain cases like in shootings of young children or political figures, therefore, agencies should use their own discretion when deciding when to use the tool (captured in the Eligibility Review step). For eligible cases, the lead detective enters information into the solvability calculator to generate an initial solvability score for the case. This score determines whether the case is classified as having low, medium, or high solvability. Next, the department can use this solvability score to determine what level of resources to allocate to the investigation based on the solvability of the case. After a follow-up investigation, the lead detective recalculates the solvability score of the case at least once more to determine if the case's solvability classification has changed. After all leads have been exhausted and resources have been extinguished based on the case's solvability classification, the department can suspend the investigation while being confident that a transparent, consistent, and evidence-based process was applied to decision-making about how to allocate investigative resources across nonfatal shooting cases.

Instructions for Using the Solvability Calculator: User Guide

The National Case Closed Project has developed a user guide for its solvability calculator. It describes the tool's development, its intended use, and limitations and considerations in its use. It also provides technical instructions for using the tool and for interpreting results of the tool. Finally, it discusses future directions in the use of the tool. Users are strongly encouraged to download and read through this user guide before opening the calculator to ensure they use it properly. Click the link below to download the user guide.

Solvability Calculator: Download the Tool

This Excel-based solvability calculator was designed to calculate the solvability of an active nonfatal shooting case based on evidence-informed solvability factors and their designated solvability scores. The lead detective on the case, or another designated individual, should collect relevant case facts before entering information into the solvability calculator. Users are strongly encouraged to download and read through the user guide (see link above) before opening the calculator to ensure they use the calculator correctly and interpret the results accurately. Click the link below to download the solvability calculator.

Limitations and Considerations in Using the Solvability Calculator

1. Research on solvability factors in cases of severe violence (typically homicide) is limited, and factors may vary across jurisdictions or change over time. The National Case Closed Project encourages law enforcement agencies who use the tool to report back on the tool's accuracy in predicting the solvability of nonfatal shooting cases and its ability to avoid any negative consequences of solvability triaging such as inequalities in the distribution of investigative resources. New versions of the solvability calculator will be released when changes are made to the tool.
2. Agencies should consider how the solvability calculator can be formally incorporated into nonfatal shooting investigations. These procedures should describe when the calculator should be used, how to interpret the solvability score, and how to allocate resources accordingly. Ensure that these procedures are documented into policy and that anyone involved in a nonfatal shooting investigation has been trained on them. Departments may want to supplement the solvability calculator with clinical judgement about the effort and resources to dedicate to a nonfatal shooting investigation, which is the eligibility review stage shown above. Any room for discretion in the use of the tool should be clearly documented in policy.
3. The solvability calculator depends on accurate information about the case. The lead detective, or whoever is responsible for completing the solvability calculator, should ensure that they have current and accurate information on each solvability factor before using the calculator to generate a solvability score for the case. They should also verify that a thorough investigation has been conducted to date. A case that has not been thoroughly investigated may show an artificially low solvability score, which would ultimately affect the resources allocated to that investigation, and, in turn, its likelihood of being solved.
4. The solvability calculator was developed for use in active nonfatal shooting investigations. It may not accurately predict solvability in cases involving other crime types or in cold cases.

See the User Guide for more information on limitations and considerations in using the solvability calculator.

For questions or feedback about the solvability calculator, please contact us at caseclosed@rti.org. We encourage you to review other resources on effectively investigating fatal and nonfatal shootings that are available on the National Case Closed Project's website.