Simulations of Military Operations Other Than War

DEXES Executive Summary


DEXES is a simulation program designed to support analysis and training for Military Operations Other Than War (MOOTW). It was developed during 1995-98 by the US Southern Command (J5 Plans, Analysis, and Simulation division), and is currently used by the J7 Joint Theater Analysis and Gaming division.

At the heart of DEXES is a dynamic mathematical model of society, encompassing economic, social, political, and public health variables. This model generates the societal reactions to actions taken (or not taken) by the peacekeeping forces, hostile military and political players, and non-governmental organizations. The current state of society is continuously available to players in the form of charts, graphs, colored maps, and tables.

Events in the game can be scripted in advance, by means of a simple spreadsheet which gives the event description, its day and time, and its direct consequences. Special non-scripted events may also be created, which are triggered either randomly or whenever a specified situation or condition is encountered. Actions that each unit can take are detailed in another spreadsheet, as are the essential characteristics and capabilities of each type of unit.

As the simulation unfolds, scripted and triggered events occur, and military units and other entities take actions in response. All events and actions have consequences that are automatically implemented as changes in the state variables of the underlying model of society. Changes in any one state variable cause further changes in other variables, as the indirect effects of an action ripple through the causal web of the model. In this way analysts and trainees can see the long-run consequences of their actions.

DEXES is often used in exercises to project the state of a society weeks and months ahead into the future, using its internal model of societal dynamics and the long-range plans that each team has specified for the units under its control. This capability is particularly important when an exercise design includes time-jumps that separate intervals of real-time play. The DEXES simulation bridges each time-jump by running its model forward (in accelerated mode) to the beginning of the next interval of real-time. DEXES output is then used by the players to establish the current situation at the beginning of each real-time interval.

DEXES state variables range from "hard" quantitative variables (e.g. daily civilian mortality), to "soft" qualititative variables (e.g. ethnic distrust). For the purposes of simulation, all variables are treated as quantitative in the mathematical model, using standard methods for modeling from sociology, political science, and economics. Furthermore, the dynamic model is stochastic, meaning that all effects are subject to small amounts of random variation, as specified by the scenario designer.

DEXES has been used successfully by SouthCom in 24 international exercises (15 peacekeeping, six humanitarian disaster relief , and three crisis management) in twelve countries, with participation by the United Nations and dozens of international and non-governmental organizations.

History of DEXES

Downloadable DEXES documentation, in Adobe Acrobat format (pdf files):

DEXES Scenario Designer's Guide
DEXES User's Guide
DEXES Output
DEXES Data Requirements for Analysis