When the Headline Hits Home: Perceived Risk of Military Conflict and Preferences for Defense Policy

Last registered on March 10, 2026
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Pre-Trial

Trial Information

General Information

Title
When the Headline Hits Home: Perceived Risk of Military Conflict and Preferences for Defense Policy
RCT ID
AEARCTR-0018056
Initial registration date
March 07, 2026

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
March 10, 2026, 10:34 AM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.

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Primary Investigator

Name
Clara-Marie Pache
Affiliation
Leipzig University
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Other Primary Investigator(s)

PI Name
Sebastian Blesse
PI Affiliation
Leipzig University
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PI Name
Lergetporer Philipp
PI Affiliation
Technical University of Munich
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PI Name
Helen Zeidler
PI Affiliation
Technical University of Munich
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Additional Trial Information

Status
In development
Start date
2026-03-09
End date
2028-12-31
Keywords
Crime, Violence, & Conflict
Additional Keywords
Geopolitical Risk, Defense Policy, Information Provision, Belief Updating
JEL code(s)
H56, D83, C90, F51
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Since Russia’s full-scale invasion of Ukraine in February 2022, defense policy has re-emerged as central topic in political debates across Europe. Beyond the severe consequences for Ukraine, concerns about further escalation and the potential for increased German involvement have prompted fundamental debates about security and defense policy in Germany.

This study examines how perceived risks of military conflict causally affect defense policy preferences. We conduct a survey experiment in Germany in which respondents are randomly provided with factual information about military experts’ assessments of the probability of Germany’s involvement in a direct military conflict with Russia within the next five years. Treatments vary along two dimensions: (1) the geographical scope of the conflict (NATO–Russia vs. Germany–Russia on German territory) and (2) the expert assessment on the probability (30% vs. 50%).

This design allows us to assess how expert information about different conflict scenarios and risk levels affect individuals’ security-related concerns and defense policy preferences, both on a national level and regarding international cooperation among EU members. Additionally, we analyze how exposure to expert risk assessments shapes support for increased defense spending.

By experimentally varying both the level and territorial scope of communicated conflict risk, this study provides causal evidence on how perceived military conflict risk influences defense policy preferences.
External Link(s)

Registration Citation

Citation
Blesse, Sebastian et al. 2026. "When the Headline Hits Home: Perceived Risk of Military Conflict and Preferences for Defense Policy." AEA RCT Registry. March 10. https://doi.org/10.1257/rct.18056-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
We conduct a survey experiment with a representative sample of the German population stratified by age, gender, education, employment status as well as state of residence. With a sample size of approximately 5,000 individuals, we field the study with the survey company Bilendi and implement it in Qualtrics. Survey participants answer the questions autonomously on their own digital devices.

The between-subject experiment has the following structure: With equal probability, respondents will be randomly assigned to one of four treatment groups or the control group. The randomization is implemented within Qualtrics. Subjects are provided with the survey link via the survey company.

In addition, for Outcome 7 respondents are independently randomized with equal probability to receive or not receive an informational statement indicating that the average responses will be forwarded to federal politicians in the Bundestag, in order to study whether perceived political consequentiality affects expressed policy support.
Intervention Start Date
2026-03-09
Intervention End Date
2026-04-30

Primary Outcomes

Primary Outcomes (end points)
Our primary outcomes of interest are the (i) posterior beliefs, (ii) concerns about military conflict with Russia, (iii) support for defense policies, (iv) preferences for defense spending.
Primary Outcomes (explanation)
In the empirical analysis, we will analyze treatment effects on all outcome measures. We will additionally summarize the items in outcomes 1 into one “concerns” index, outcomes 2, 5, and 6 into a “support for defense policies” index, and outcomes 3 and 4 into a “preferences for defense spending” index.

Secondary Outcomes

Secondary Outcomes (end points)
We will investigate heterogeneities by respondents’ prior beliefs in order to investigate the belief-updating process underlying possible treatment effects.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We conduct a survey experiment with a representative sample of about 5,000 individuals. The survey is conducted as an online questionnaire.

Our experiment is structured as follows:

Stage 1: opening statements

Stage 2: prior beliefs

Stage 3: randomized information provision

Stage 4: Posterior Beliefs

Stage 5: Post-treatment outcomes

Stage 6: General security-related views

Stage 7: Debriefing
Experimental Design Details
Not available
Randomization Method
Randomization is carried out by the survey tool Qualtrics.
Randomization Unit
At the individual level
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
5,000
Sample size: planned number of observations
5,000
Sample size (or number of clusters) by treatment arms
Approximately 1,000 respondents will be assigned to each of the experimental groups with equal probability. In addition, there is an independent randomization in which half of the respondents are randomly assigned to receive an informational statement associated with Outcome 7.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
No
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
Ethics committee of the Technical University of Munich
IRB Approval Date
2026-01-26
IRB Approval Number
2026-7-NM-BA
Analysis Plan