The AAQ-S is a 21 item measure of psychological flexibility/inflexibility with stigmatizing thoughts. The measure includes two subscales (psychological flexibility and psychological inflexibility), which can be analyzed separately or combined into a total score.
The AAQ-S can be downloaded from the Utah State University ACT Research Group.
The citation for the measurement development/validation paper is:
Trigueros, R., Navarro-Gómez, N., Aguilar-Parra, J. M., & Cangas, A. J. (2020). Factorial Structure and Measurement Invariance of the Acceptance and Action Questionnaire-Stigma (AAQ-S) in Spain. International Journal of Environmental Research and Public Health, 17(2), 658. https://doi.org/10.3390/ijerph17020658
Levin, M.E., Luoma, J.B., Lillis, J., Hayes, S.C. & Vilardaga, R. (2014). Developing a measure of psychological flexibility with stigmatizing thoughts. Journal of Contextual Behavioral Science, 3, 21-26.