How to Collect Data on the ABCs of Behavior

How to Collect Data on the ABCs of Behavior

A familiar question behavior analysts receive from parents and teachers about problem behavior is, “Why does my child do that?” To gather information about the ‘why’ or function of a problem behavior, we need to collect data.  Frequently, the first place a behavior analyst begins when examining a new or frequent problem behavior is ABC data collection.

What is ABC Data?

ABC data refers to one of the core facets of Applied Behavior Analysis known as the three-term contingency.

Antecedent –  Behavior – Consequence

ABC data allows behavior analysts, teachers, and other ABA professionals to learn more about why an individual may engage in a behavior and create a hypothesis about the function of the behavior.  In ABC data collection, the behavior analyst monitors antecedents, behaviors, and consequences of a particular target response to increase or decrease for some time.  That period of observation might be for several days or several weeks, depending on how frequently the behavior occurs. Usually, ABC data requires all instances of the behavior of interest to the behavior analyst to be recorded.

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Before you review the different Consider each of the ABC’s included in ABA data collection:


Antecedents are the environmental conditions that occur immediately before the target behavior. In ABC data collection, antecedent information involves a detailed description of what happened just before the response.  Some questions you might ask yourself when collecting antecedent data on the ABCs of behavior:

  • In what setting did the behavior occur?
  • What time of day did the behavior occur?
  • Were there other people nearby? What were those people doing?
  • Did the behavior occur during a particular activity, transition, or downtime?
  • What was the environment like at the time (e.g., noise level, temperature, number of people around, specific items in proximity to the individual)?


The “B” in the three-term contingency and ABC data collection stands for behavior. The behavior recorded in ABC data collection should be whatever target response is of interest to the observer.  Sometimes it may be problem behavior like tantrums, refusals, or aggression.  On other occasions, it may be prosocial behaviors like ‘talking to friends’ or ‘hand-raising.’ When recording the target behavior, remember to be as specific and descriptive as possible.


The “C” in ABC data and the three-term contingency refers to the consequence.  Consequences are often the most valuable piece of information obtained from ABC data collection. They describe the events that happen immediately after the target behavior.

Consequence information helps the behavior analyst begin to identify a hypothesis or pattern of why the behavior continues to occur.  If the behavior reliably results in an adult providing attention or getting out of a difficult task, we can begin to see ways in which the response might function or happen for attention or escape. Some questions you might ask yourself when collecting the consequence data in ABC data collection include:

  • What did the individual do immediately after the behavior?
  • What did others around him or her do?
  • If the behavior occurred during a particular activity, transition, or downtime, did that activity continue, or did it stop?
  • What changes in the environment occurred as a result of the behavior (e.g., dimmed the lights, the loud music turned off, etc.)

Why do we use ABC Data Collection?

As you can see, ABC data collection provides a large amount of information about a particular behavior of interest. As a form of direct observation, ABC data allows a behavior analyst to understand better what happens before and after a specific behavior occurs. Knowing what motivated or maintained the problem behavior in the first place can result in better choices about later interventions.

ABC data has also gained popularity among behavior analysts because, among all forms of data collection, it’s relatively simple to collect.  Most parents, special education teachers, and caregivers can be taught the ABC’s of behavior in a few minutes.  Electronic and app-based systems to collect ABC data make the process even easier.  Without a lot of training, the behavior analyst can gather a large amount of valuable information about an individual’s behavior.

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How to analyze ABC Data

Once the behavior analyst collects ABC data, the important work begins.  The behavior analyst must examine each logged behavior both individually and collectively to determine if an intervention is necessary and what types of intervention options may be the best.  While each circumstance requires individualized analysis, here are some basic questions to ask when analyzing ABC data:

  • Do all the entries provide clear information? Sometimes ABC data entries may be made in short-hand or brief notes, particularly in the instances where the data collection occurs for aggressive or tantrum behaviors that demand increased attention.  Spend some time going through each entry and confirm that the data collection makes sense.  If more information is needed, ask the therapist, paraprofessional, or parent to provide more details.
  • What trends occur in the time of day and location? Start by analyzing when and where the behavior occurs.  Look for patterns in the time of day, place, or environment where the response occurs.  If the problem happens throughout the day versus only happens at one time of day, like during a morning routine, it may change the type of intervention selected.
  • What trends occur in the environment immediately prior? Next, examine what happens immediately prior in the environment to evoke the behavior.  Sometimes there may be clear triggers, like the request to get dressed in the morning.  In other situations, the trigger may be more general and come in the form of a request to transition or a social initiation.  Knowing the specific environmental trigger can help identify the types of replacement behaviors that the individual may need to learn to be more successful.
  • What variability in the behavior do you notice? Sometimes the data on the behavior itself can offer valuable information.  Does the behavior worsen or become more intense over time?  Does the magnitude or duration of the behavior change depend on the time of day or the environmental conditions?  Do certain aspects of the behavior change depending on who else is in the environment?  Answering all of these questions can help build the best intervention options to address the particular facets of the behavior.
  • What trends occur in the environment immediately after? Given how ABC data informs our understanding of the function of a behavior, examine trends in the consequences as well. Does the individual reliably receive attention or escape from completing a task? Are the consequences consistent, or do they vary between caregivers?  If the outcomes differ, how does that impact the behavior or antecedents?   

Amy Sippl

Applied Behavior Analysis | Saint Cloud State University

Bachelor of Arts (B.A.), Psychology | University of Minnesota

April 2020

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