This United States Army policy, Army Regulation AR 70-38 Research, Development, Test and Evaluation of Materiel for Worldwide Use June 2020, prescribes policies, responsibilities, and planning guidance for inclusion of the global operational environment climatic and natural environment factors in the research, development, test and evaluation of materiel used in combat by the Army.

This regulation applies to the Regular Army, the Army National Guard/Army National Guard of the United States, and the U.S. Army Reserve, unless otherwise stated. It also applies to items of materiel developed for use by the Army unless otherwise stated. It applies to items of materiel developed by another Service to meet Army requirements and where the Army approves the capability requirements documents; has budget responsibility; and is the user.

This regulation establishes policy, identifies responsibilities, and provides climate and terrain factors to ensure mission capable and reliable Army materiel for worldwide operation. In addition to design guidance, this regulation describes a global operational environment (GOE) framework and operational environment (OE) analogs defined by climate and terrain factors to provide direct comparisons of areas of the world from the aspect of performance of Army materiel wherever based or potentially deployed. Application of this regulation ensures that the research, development, test and evaluation (RDTE) decision-making process considers the natural environmental factors that affect equipment performance when preparing capability requirements documents, operation mode summary/mission profile (OMS/MP), and design criteria for acquisition specifications. Early consideration of design criteria and the OE reduces program risk and lowers life-cycle costs by addressing environmental challenges and potential reliability shortfalls early in the RDTE process when corrective actions have minimum overall impact. Army equipment tends to remain in the active inventory for extended periods and is likely to be exposed to severe environmental conditions during its lifetime. Consequently, durability, operational costs, and performance over a full range of environmental factors must be considered during RDTE process.