“An experience, event, or physical, or emotional state” that makes challenging behavior more likely to occur.^[i] Examples include hunger, boredom, changes in routines, changes in medication, and lack of sleep.

[i] Artman-Meeker, K., & Hemmeter, M. L. (2014). Page. 251, Functional assessment of challenging behaviors. In M. McLean, M. L. Hemmeter, & P. Snyder (Eds.), Essential elements for assessing infants and preschoolers with special needs (pp. 242-270). Boston, MA: Pearson.