Faced with the shootdown of a military aircraft, how would U.S. decision makers respond? What if that aircraft were a drone? Much recent work argues that drones make the use of force more likely. The dominant argument is that removing pilots from harm’s way lowers the risk to friendly forces, making it easier for states to deploy drones and escalate crises. But how might drones affect what comes next? How might they shape escalation and the use of force after initially being deployed? A key determinant of whether a conflict will escalate is how actors respond to attacks on their military assets. Drones — military assets that can be attacked without hurting enemy personnel — change the calculus of retaliation.

I developed an innovative approach to explore these dynamics: the experimental wargame. The method allows observers to compare nearly identical, simultaneous wargames — a set of control games, in which a factor of interest does not appear, and a set of treatment games, in which it does. In my experiment, all participants are exposed to the same aircraft shootdown scenario, but participants in treatment games are told the downed aircraft is a drone while those in control games are told it is manned. This allows policymakers to examine whether drones affect decision-making.

The experimental wargames revealed that the deployment of drones can actually contribute to lower levels of escalation and greater crisis stability than the deployment of manned assets. These findings help explain how drones affect stability by shedding light on escalation dynamics after an initial drone deployment, something that few existing studies on drones have addressed.

My findings build upon existing research on the low barrier to drone deployment by suggesting that, once conflict has begun, states may find drones useful for limiting escalation. Indeed, states can take action using or against drones without risking significant escalation. The results should ease concerns of drone pessimists and offer valuable insights to policymakers about drones’ effects on conflict dynamics. More broadly, experimental wargaming offers a novel approach to generating insights about national security decision-making that can be used to inform military planning and policy development.

Experimental Wargaming: An Innovative Research Design

As recent War on the Rocks articles have highlighted, wargames are used to refine doctrine and strategy and prepare for contingencies. By placing national security practitioners in realistic settings without the risks and costs associated with real-world operations, wargames allow policymakers to study decision-making and explore the effects of new technologies or shifts in the geopolitical environment. A growing body of research has focused on ways to improve the quality of insights that can be drawn from wargames.

One innovative way to strengthen these insights is to use the best practices of experimental research in what I have termed an “experimental wargame.” To make a wargame experimental, it must include simultaneous “control” and “treatment” games. These parallel games place different groups of participants with similar backgrounds into wargames that are identical across all dimensions except for a specific factor of interest.

Because experimental wargames vary only the factor of interest and hold constant all other factors like the scenario, type of participants, and when the games are held, they help isolate the effect of the factor of interest. Non-experimental wargames, on the other hand, fail to hold these additional variables constant, meaning that decision-making might be influenced by environmental factors or considerations other than the factor of interest.

Experimental wargames generate a set of final decisions and a narrative that documents interaction between participants. By comparing the decisions and narrative from the control game with those from the treatment game, researchers can explore whether the factor of interest shaped the decisions of participants and the logic that underpinned these decisions.

Comparing a single control game to a single treatment game generates useful insights about the participants in that set of games. But to draw more generalizable inferences about the effect of a factor of interest, larger treatment and control groups are required. In the ideal case, an experimental wargame would include hundreds of simultaneous control and treatment games. This would allow for statistical analysis that measures the average effect of a factor of interest on decisions. This is why pharmaceutical trials typically include thousands of participants. To assess the effectiveness of a new drug, researchers compare the health outcomes among a treatment group that receives the medication with a control group that receives a placebo. Large treatment and control groups ensure that differences in health outcomes are the result of the medication and not chance or patient-specific factors.

The logistics of running even the simplest wargames, however, makes large-scale fielding challenging. As a more tractable alternative, experimental wargames can be conducted with a smaller number of control and treatment games. The smaller sample precludes statistical analysis, but comparisons between even small numbers of sample and treatment games allows researchers to observe trends in participant behavior. These trends can offer insights on the effect of a factor of interest in a way not possible with non-experimental games.

Although experimental wargames can offer valuable findings, coupling the games with other approaches, such as assessments of historical operations and modeling and simulation, can provide even richer insights.

Applying Experimental Wargaming: Drones and Crisis Escalation

I used experimental wargames to examine how decision-makers respond to the downing of an aircraft during an interstate crisis. These experimental wargames — held at MIT Lincoln Labs and Harvard University in fall 2017 — randomly assigned 28 participants with military experience to seven teams. Each team represented the same planning cell at a U.S. air operations center.

Participants took part in a one-sided game, meaning they responded to a pre-scripted scenario rather than playing against an actual opposing team. While this eliminates the realism of a dynamic interaction between forces, it was logistically simpler while still allowing for the close examination of decision-making behavior. The experimental approach, however, can be applied to larger and more complex multi-sided games.

The wargame scenario involved the fictional Central Asian states of Dakastan and Katunia. Dakastan is a U.S. ally engaged in a territorial dispute over a resource-rich border region with its autocratic neighbor, Katunia. Dakastan, which hosts a U.S. airbase, is increasingly subjected to attacks by Katunian-backed forces, prompting the United States to provide air defense and intelligence support to Dakastan.

Participants were told that a U.S. reconnaissance aircraft flying in friendly Dakastani airspace was shot down by a surface-to-air missile launched by hostile Katunian forces. The aircraft crashed, with most of the wreckage landing in Katunian-controlled territory. All participants were exposed to the identical shootdown scenario, but participants assigned to the four treatment games were told the downed aircraft was a MQ-1 Predator drone, while those in the three control games were told the aircraft was a manned MC-12 Liberty whose four-member American crew was killed. Teams were asked to develop a response to the shootdown.

As participants worked, research assistants took detailed notes documenting not only the plans developed by each team, but also the process by which participants came to their final decisions — shedding light on whether and how drones affected their decision-making.

Teams facing a drone shootdown generally avoided retaliating with military force, while those responding to the loss of a manned aircraft typically took more escalatory action by launching military strikes against Katunia and sending troops into Katunia to recover the crew’s remains. Underlying these divergent responses was the absence of captured or killed personnel in the drone scenario. Indeed, teams often explicitly joked about the fact that the drone had no humans onboard. “Where do you bury the survivors?” asked one participant. “The good thing is that there is no pilot being dragged along,” noted another.

Since the downing of a drone was seen as a lower-stakes incident, response plans avoided significant acts of military escalation. Teams frequently recommended diplomatic reactions like a demarche coupled with limited military posturing, such as providing armed escorts for future reconnaissance missions or increasing the alert status of U.S. forces in the region. No team exposed to a drone shootdown launched kinetic military operations or took steps to recover wreckage that had fallen in rival Katunia’s territory. Indeed, many participants viewed the shootdown of a drone simply as the loss of “a mostly disposable asset” that fell below the threshold that warranted a major military response.

In contrast, teams that suffered the loss of a manned asset launched far more aggressive responses. These teams all planned airstrikes on Katunian forces and most took the escalatory move of deploying troops into Katunian territory to recover the remains of downed aircrew. Airstrikes on targets including Katunian air force bases and surface-to-air missile sites were intended to roll back the options that Katunia could use in future hostilities. It appeared that these teams were more risk-tolerant and willing to escalate because they believed that losing American lives demands a significant response to punish the adversary and deter future attacks. Indeed, participants’ language often took on a passionate and emotive tone. “This represents a conflict! If they shot down our service members, we retaliate,” proclaimed one participant. Another put it more bluntly: “The gloves are off!”

By comparing the reactions of military decision-makers to the loss of drones and manned assets in otherwise identical scenarios, the experimental wargames demonstrate that drones can help mitigate escalation by eliminating both instrumental and emotional drivers of retaliation. As participants noted, “Once [you] put the body into it, it changes the interaction between states,” which means the “risk of escalation with manned [assets] is higher.”

These reduced risks of escalation suggest drones are an attractive tool for carrying out coercive diplomacy. On one hand, states may launch drones without the political or military risk associated with deploying manned assets. This may lead states to more frequently deploy drones to violate the airspace of rivals or to reinforce claims over contested areas. Indeed, China routinely flies drones near contested islands in the East China Sea to challenge Japan’s claims. At the same time, taking action against drones allows states to signal opposition to a rival’s practices, demonstrate military power to domestic audiences, or glean intelligence about an adversary’s military capabilities with less likelihood of further escalation compared to an attack on a manned platform.

Future Pathways for Experimental Wargaming

While the wargame findings offer important insights for military practitioners, policymakers and scholars interested in the specific effects of drone use, the experimental wargaming methodology offers far wider utility. Wargame designers can run experimental games that manipulate a range of other factors that matter for operational and contingency planning.

For example, planners interested in escalation dynamics in East Asia might conduct an experimental wargame that varies whether Chinese warships or white-hulled Chinese coast guard vessels carry out aggressive action against U.S. Navy ships. This design allows planners to observe whether U.S. participants respond differently to actions carried out by military vessels than to the same actions carried out by coast guard ships. Similarly, a Europe-focused wargame might vary the means by which Russia carries out subversive activity in its near abroad. Some wargaming teams might be told that a power plant is disabled by “little green men,” while other teams are informed the same plant is disabled by a Russian airstrike or a suspected Russian cyber attack.

To be sure, wargames are not predictive and cannot precisely foretell how actual crises will unfold. Experimental wargames can, however, allow policymakers and researchers to use methods borrowed from social science to examine how specific features affect decision-making — and in some cases, uncover counterintuitive findings like the stabilizing nature of drones. Such findings can inform planning and strategy, helping militaries refine their practices in a simulated and safe environment rather than during real-world contingencies.

Erik Lin-Greenberg (@eriklg) is a Carnegie pre-doctoral fellow at the Center for International Security and Cooperation at Stanford University and a PhD candidate in political science at Columbia University.

Image: U.S. Air Force photo by Senior Airman Cory D. Payne