C-3: Measure occurrence (E.g., Frequency, Rate, Percentage) ©

Target Terms: Frequency, Rate, Percentage


Definition: How often a behavior occurs.  

Example in everyday context: Checking your phone 120 times would be the frequency that you checked you phone. 

Example in clinical context: A BCBA is observing a student in their classroom and observes the them call out 17 times while sitting at their desk. 

Example in supervision/consultation context: A supervisor observes their supervisee provide praise to a student when conducting an intensive teaching session and counts how often the supervisee says, “Nice job!” to the student. The supervisor counts 24 instances of the supervisee saying “Nice job” to the student. 

Why it matters: Frequency is used when you want to count how many times a behavior is occurring. Behaviors may occur too often or too little and may need to be targeting for intervention. 


Definition: A measure of how often a behavior occurs over an amount of time. Rate is like frequency, except with a time component added.

Example in everyday context: You eat 30 potato chips in 15 minutes.  

Example in clinical context: A child engages in hand to head self-injury five times in 20 minutes. 

Example in supervision/consultation context: A supervisee is completing 10 quiz questions in 11 minutes. 

Why it matters: Rate is used when you want to know how much a behavior is occurring over time. In certain instances, rate may be targeted to increase or decrease depending on the behavior. 


Definition: A measurement expressed as a portion of each hundred. 

Example in everyday context: Your phone tracking app indicates that you spend 42% of your daily phone time using social media.

Example in clinical context:
A behavior analyst calculates that their client engaged in aggression in 20% of data intervals over the course of the day.

Example in supervision/consultation context:
A supervisor takes data on a supervisee’s implementation of an FCT protocol. The supervisee delivered the intervention with 90% fidelity.

Why it matters:
Percentage can be useful to get a snapshot of how a person’s behavior reduction or skill acquisition is progressing. Percentages have limitations because they do not tell us all necessary clinical information. For example, if a client is consistently getting 90% on letter identification, we don’t know if he is making “random” errors or if there is a pattern of skill deficit.

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