Sudden societal events pose a challenge for survey research because public reactions often unfold rapidly and are difficult to capture with conventional fieldwork designs. This paper presents an event-triggered survey approach implemented within an intensive smartphone 
app-based panel study during the 2025 German federal election campaign. Following a car attack in Munich on February 13, 2025, an event-specific questionnaire was sent to participants to measure immediate awareness, emotional reactions, evaluations of political and media 
responses, and perceived consequences for the election campaign.

The questionnaire achieved a high compliance rate of 75.4%. Most respondents were already aware of the event, and the majority completed the questionnaire shortly after distribution. Descriptive results show moderate perceived personal aąectedness and pronounced emotional reactions, especially worry, resentment, and anger. Respondents expected the car attack to strongly influence the election campaign but were more reserved in their normative assessments of whether it should do so.

Beyond these immediate event-specific measures, the study design allowed linking the reactions to the event to political attitudes and personality traits measured before the car attack. Respondents with more restrictive immigration attitudes, more right-leaning political orientations, and stronger authoritarian attitudes reported higher levels of personal aąectedness, whereas neuroticism showed no significant association. The fact that political attitudes and personality traits were measured prior to the car attack, while reactions to the event were captured afterward, reduces the risk of post-event rationalization and demonstrates the analytical value of combining event-triggered questionnaires with longitudinal panel infrastructures.

Overall, the study shows that the implementation of event-triggered surveys within intensive smartphone app-based panel studies is a promising tool for capturing immediate reactions to salient societal events in near real time, while also highlighting challenges related to timing, questionnaire preparation, and event salience.

This white paper provides a comprehensive programme description for the Infrastructure Priority Programme "New Data Spaces for the Social Sciences" (SPP 2431), explaining the scientific context and the urgent need to modernize traditional survey research. It outlines a strategic response to declining participation rates and rising fieldwork costs by integrating technological innovations into empirical social research.

The paper describes the four core research areas where methodological innovation is critical:

1. Exploration and Integration 

2. Respondent-Driven Designs 

3. Instrument Validity 

4. Multimodal Data Acquisition 

Additionally, the paper provides a detailed description of the programme’s structure, including its governance framework and the ENTAILab. As the central research hub, the ENTAILab facilitates the integration of these innovations into major existing panel studies and provides supports to individual projects in the areas of data quality, reproducibility, data protection, and ethical standards.