Further analysis of the unintentional discharge of firearms in law enforcement

Not according to plan: Cognitive failures in marksmanship due to effects of expertise, unknown environments, and the likelihood of shooting unintended targets

Shooting errors have multi-faceted causes with contributing factors that include sensorimotor activity and cognitive failures. Empirical investigations often assess mental errors through threat identification, yet other cognitive failures could contribute to poor outcomes. The current study explored several possible sources of cognitive failures unrelated to threat identification with live fire exercises. Experiment 1 examined a national shooting competition to compare marksmanship accuracy, expertise, and planning in the likelihood of hitting no-shoot or unintended targets. Experts demonstrated an inverse speed/accuracy trade-off and fired upon fewer no-shoot targets than lesser skilled shooters, yet overall, greater opportunity to plan produced more no-shoot errors, thereby demonstrating an increase in cognitive errors. Experiment 2 replicated and extended this finding under conditions accounting for target type, location, and number. These findings further dissociate the roles of marksmanship and cognition in shooting errors while suggesting that marksmanship evaluations should be re-designed to better incorporate cognitive variables.

Examining the impact of grip strength and officer gender on shooting performance

BACKGROUND

Effective shooting performance relies heavily on sufficient grip strength. However, some standard issue pistols used by police services may have a trigger weight that causes problems for officers with insufficient grip strength, including female officers. The current study aimed to replicate previous findings, which show that grip strength is positively related to shooting performance. We also sought to determine what grip strength is required to achieve proficient scores on a standard police pistol qualification (PPQ) when a heavy trigger weight (i.e., 8lbs-12lbs) is used. Finally, we explored the relationship between officer gender and PPQ scores to determine if grip strength plays a mediating role in this relationship.

METHOD

The dominant hand grip strength (in lbs) of 86 male and 32 female officers were recorded prior to their participation in their agency mandated annual PPQ. Officer gender, grip strength, and PPQ scores were analyzed to explore how they related to one another.

RESULTS

Grip strength significantly impacted officers' ability to pass the PPQ, with female officers possessing lower grip strength compared to male officers, as well as achieving poorer scores on the PPQ. We determined that grip strengths in the range of 80lbs and 125lbs were needed to score approximately 85 % and 90 % on the PPQ, respectively; exceeding that of the average grip strength for the female officers in the study (M = 77.5lbs). Mediation analysis suggested that grip strength may mediate the relationship between officer gender and shooting performance, but studies with more power are needed to confirm that.

CONCLUSION

To improve shooting performance as well as public and police safety, law enforcement agencies may need to consider including grip strength training in their conditioning regime or examine the adoption pistols with a lighter trigger pull weight (e.g., 6lbs).

Developing scenarios that evoke shoot/don't-shoot errors

Multiple errors can occur in a use-of-force scenario, although some critical errors involve unintended casualties where the target should never have been fired upon. Training instructors utilize a variety of methods to ensure military and law enforcement personnel do not inflict unintended casualties. However, there is little empirical evidence about the best methods to design a shooting simulation that might evoke these errors, which is critical to ensure the validity of any assessment or training exercise. The current study analyzed performance across a variety of simulated shooting scenarios developed and applied for military training purposes. Several factors were assessed based upon either the scenario or human performance. Scenario type, number of shots fired, and the ratio of hostiles-to-non-hostiles were significant predictors for the likelihood of inflicting an unintended casualty. This collected evidence should help improve scenario design for future training simulations that will help avoid these critical shooting errors.

Development of a Novel Finger-Trigger Interface for Trigger Pull Measurement

Trigger pull is the force that needs to be exerted on the trigger to discharge a firearm. The measurement of trigger pull can assist in the evaluation of the safety, function, and manufacturing characteristics associated with a firearm during the forensic firearm examination process. Nonetheless, the accuracy and uncertainty of trigger pull measurements may be affected by the measuring device, test procedure, and environmental conditions. In this work, an innovative finger-trigger interface device was developed to facilitate accurate trigger pull measurements. The idea was to reduce the variation related to the position of the measurement device on the trigger in existing measuring methods and devices. Three force sensors based on different technologies were initially evaluated. While two of the three sensors failed to produce data, the miniature capacitive plate sensor exhibited high precision and a linear response over the range of typical trigger pulls. To examine the effects of the finger-trigger interface on trigger pull measurement, different sensor housing prototypes were designed in silico and 3D printed for the construction of three finger-trigger interface devices. The performance of each finger-trigger interface device was evaluated by measuring the trigger pulls of several selected firearms and comparing the data to a previously published study. Our preliminary results demonstrated the novel finger-trigger interface device offered a new way to measure trigger pull in situ with acceptable accuracy and precision.