I am looking for some good validated measures to assess endorsement of or acceptance of violence against outgroup members of differing political alignment. Many thanks.
This scale has been used in assessments with youth and might be of interest. It has been examined across groups and countries.
Raine, A., Dodge, K., Loeber, R., Gatzke‐Kopp, L., Lynam, D., Reynolds, C., ... & Liu, J. (2006). The reactive–proactive aggression questionnaire: Differential correlates of reactive and proactive aggression in adolescent boys. Aggressive Behavior: Official Journal of the International Society for Research on Aggression, 32(2), 159-171.
Dinić, B. M., Raine, A., Vujić, A., & van Dongen, J. D. (2020). Cross–cultural Validity of the Reactive–Proactive Aggression Questionnaire Among Adults Across Five Countries. Journal of interpersonal violence, 0886260520966672.
ANCODI Hypothesis has been used to assess the development of intergroup aggression. Hope it helps.
Matsumoto, D., Frank, M. G., & Hwang, H. C. (2015). The Role of Intergroup Emotions in Political Violence. Current Directions in Psychological Science, 24(5), 369-373. https://doi.org/10.1177/0963721415595023
Matsumoto, D., Hwang, H. C., & Frank, M. G. (2016). The effects of incidental anger, contempt, and disgust on hostile language and implicit behaviors: Emotion and intergroup hostility. Journal of Applied Social Psychology, 46(8), 437-452. https://doi.org/10.1111/jasp.12374
Matsumoto, D., Hwang, H. C., & Frank, M. G. (2017). Emotion and Aggressive Intergroup Cognitions: The ANCODI Hypothesis. Aggressive Behaviour, 43, 93-107.