Combat Stress: A Collateral Effect in the Operational Effectiveness Loss Multiplier (OELM) Methodology

An IDA research team designed the Operational Effectiveness Analysis (OEA) methodology to estimate a military unit’s operational effectiveness on the battlefield following a chemical, biological, radiological, and nuclear (CBRN) event. As part of the OEA effort, the team developed the Operational Effectiveness Loss Multiplier (OELM) methodology to examine the collateral effects of CBRN events on operational effectiveness. Within the OELM methodology, combat stress is viewed as a collateral effect arising from the conditions and experience of CBRN events. The potential of combat stress to degrade individual and unit operational effectiveness makes it an important aspect of the OEA and OELM research and methodologies. This document discusses combat stress and its implications on operational effectiveness; combat and operational stress reaction (COSR) in service members; and civilian psychological casualties (CPC) and combat stress casualties (CSC) as a result of CBRN and non-CBRN events. It establishes clear and formal definitions of terms relevant to combat stress; discusses the current data available to model and estimate CPC and CSC resulting from CBRN and non-CBRN events; and proposes further research to aid in the estimation of CSC and CPC in the future.