Frequency, Duration, and Intensity is a type of data collection that may assist in defining a challenging behavior. It is a perfect measurement to include in a Functional Behavior Assessment (FBA). Frequency: The number of times an event occurs within a given time frame. For example, how often someone walks out of class without permission.Duration: The amount of time an event takes place. For example, how long a student disrupts the learning environment.Intensity: How hard an event occurs. For