Report

Measuring lethality: Army combat power and force design

This report from UK think tank RUSI addresses the utility of measuring lethality as a focal point in force design.

With the UK and US military facing potential numerical disadvantages in future conflicts, this Research Paper explores how lethality – defined as the rate at which a force inflicts damage relative to the casualties it incurs – can be used as a metric to guide force development and ensure operational success. Lethality should be understood as the output of combat power, or an attempt to predict effect rather than inputs to operations.​

Key recommendations include:

Adopt a multi-metric approach to measuring lethality: Avoid oversimplified, aggregated metrics that obscure critical dependencies. Instead, measure lethality using four distinct metrics: overmatch, potential, endurance and efficiency.​

Develop an overmatch matrix: Map out enemy systems and align British Army capabilities to evaluate the proportion of the enemy that is overmatched or held at risk.​

Evaluate potential lethality: Assess the maximum damage a unit can inflict under optimal conditions and identify gaps in training or capability that hinder performance relative to that potential.​

Focus on endurance: Measure how long a force can sustain lethal output before requiring resupply or rotation, emphasising survivability and logistical support.​

Prioritise efficiency: Evaluate weapons performance relative to the cost and industrial capacity to sustain effect, to enable lethality to be maintained over the course of a protracted conflict.