Discontinuous measurement in ABA therapy is a data collection method where therapists record samples of a child’s behavior at set intervals, rather than tracking every moment it occurs. The three types — partial-interval recording, whole-interval recording, and momentary time sampling — each check in at different points to show how behavior changes over time.
You might notice your child’s RBT pausing to jot something down at certain moments during a session, rather than watching and recording constantly. That’s this method in action — a fast, practical way to gather meaningful data without tracking every second.
Data collection is a key part of how ABA therapy works — it’s how the care team knows whether your child is making progress. But that doesn’t always mean tracking every second of a session. For some behaviors, checking in at consistent intervals gives the team enough information to spot patterns and track growth over time.
In this article, you’ll learn how the three types of discontinuous measurement work, why a therapist may choose one over another, and how the data helps your child’s care team track progress.
Why Does ABA Therapy Use Discontinuous Measurement?
Recording a behavior every time it happens isn’t always feasible — especially when the therapist is conducting a group session or observing a long-lasting behavior.
In these situations, discontinuous measurement offers a great balance of speed and accuracy to make data collection easier — even in busier environments.
Continuous vs discontinuous measurement
ABA therapists use both continuous and discontinuous measurement to track behavior and progress. The difference between the two is how much of the behavior they record.
Continuous measurement tracks a behavior every time it happens — like counting how often a child asks for help, timing independent play, or tracking a safety behavior such as aggression or leaving a safe area. It gives an exact count, but it requires full attention — so it may be less practical when a therapist is balancing data collection with other responsibilities.
Discontinuous measurement divides the observation period into intervals and records samples of the behavior instead. It’s especially useful for behaviors that happen too often to count one by one, like repetitive vocalizations. It also works well for behaviors that last a long time, such as staying engaged in independent work, or in situations where the RBT is teaching or supporting the child at the same time, like a classroom or group activity.
Why sampling behavior still gives useful data
Discontinuous measurement doesn’t capture every moment, so the data is an estimate rather than an exact count. But when collected consistently, it can still show useful patterns — such as whether a child is staying on-task more often, participating in activities for longer, or engaging less often in a behavior the team is working to reduce.
Importantly, research shows that discontinuous methods can provide useful estimates of behavior, as long as the method is chosen carefully based on the behavior and goals.[1]
Therapists calculate the percentage of intervals in which the behavior occurred and plot those percentages on a graph. Looking at those percentages across sessions helps the care team see whether the behavior is changing in the direction of your child’s goal.
How often therapists check matters, too. Research on discontinuous measurement found that shorter observation intervals generally produced more accurate estimates of behavior than longer ones.[2] That’s one reason BCBAs consider how often behavior should be checked when setting up data collection.
What Are the Main Types of Discontinuous Measurement?
There are three main types of discontinuous measurement: partial-interval recording, whole-interval recording, and momentary time sampling. All three divide an observation period into smaller intervals, but they differ in when a behavior needs to occur for the therapist to record it.
Partial-interval recording
Partial-interval recording (PIR) records whether a behavior happens at any point during an interval. It’s often used for behaviors the care team wants to occur less often, such as calling out or repetitive vocalizations. Because even a brief occurrence counts, PIR may overestimate how much the behavior actually occurs.
Whole-interval recording
Whole-interval recording (WIR) records a behavior only if it happens throughout the entire interval. It’s often used for skills the care team wants a child to maintain for longer periods, such as staying on-task, sitting during an activity, or playing independently. Because the behavior must continue for the whole interval to count, WIR may underestimate how much it actually occurs.
Momentary time sampling
Momentary time sampling (MTS) records whether a behavior is happening at one specific moment, usually at the end of an interval. It’s often used for longer-lasting behaviors — such as participating in an activity — or in group settings where closer observation is challenging. Because behavior between those scheduled checks isn’t recorded, MTS may miss some occurrences.
When Does United Care ABA Use This Method?
Practicing new skills doesn’t have to take place only during one-on-one ABA therapy sessions. At United Care ABA, we bring support into school routines, group activities, and other everyday experiences in the community.
In these busy situations, discontinuous measurement can make it easier for therapists to support the child or group in the moment while also tracking progress.
Group settings, school, and community sessions
In-school ABA therapy or group therapy sessions give children opportunities to practice ABA skills during real routines, around other people and distractions. However, tracking behavior continuously can be difficult for therapists or educators who are juggling multiple responsibilities.
Discontinuous measurement reduces the burden of observation while still collecting helpful estimates of behavior trends. For example, interval data might show whether a child stays engaged across different parts of the school day or remains near a caregiver during different stages of a community outing.
How data collection connects to your child’s progress reports
As a parent, you want to know whether therapy is making a difference for your child. Data collection gives your child’s care team a way to measure that progress rather than relying on guesswork or impressions.
One way that progress is shared is through progress reports. These written reviews summarize your child’s treatment goals, progress, and areas that may still need support. Key metrics are turned into percentages and plotted on graphs to make changes in behavior frequency or duration easier to see over time.
This information can also be useful when care coordination with your team involves other people supporting your child, such as teachers, doctors, or other therapists. It gives everyone a clearer picture of what your child is working on and how they’re progressing.
How Are Behavior Technicians Trained on Data Collection?
Your child’s Registered Behavior Technician (RBT) is typically the person collecting data during therapy, so learning how to record behavior accurately is an important part of their training.
Our RBTs complete a 40-hour training course and competency assessment, as required by the Behavior Analyst Certification Board (BACB).[3] During therapy, they continue working under BCBA supervision and receive feedback on how they collect and record data.
Building accuracy through supervision and practice
At United Care ABA, our BCBAs provide ongoing supervision as RBTs put these skills into practice. That may include making sure the RBT is identifying the right behavior, following the measurement method correctly, and recording only what they observe.
This ongoing guidance helps keep your child’s data consistent and gives the BCBA dependable information to use when tracking progress and guiding treatment.
Ready to Learn More About Your Child’s Therapy Data?
In ABA therapy, data isn’t an afterthought — it’s woven into every session and the planning that happens behind the scenes. It helps your child’s team understand their progress, respond when something isn’t working, and keep treatment focused on what your child needs most.
At United Care ABA, we understand that many skills are best practiced and measured during the everyday routines where your child actually uses them. Discontinuous measurement helps us capture progress in those moments while staying focused on supporting your child.
Explore our parent resources to learn more about ABA therapy, or contact United Care ABA to get started.
FAQs
What is an example of discontinuous measurement in ABA?
A common example is partial-interval recording, where a therapist breaks a session into 5-minute blocks and marks whether hand-flapping happened at any point in each block, rather than counting every occurrence.
What is the difference between continuous and discontinuous measurement?
Continuous measurement records every single instance of a behavior, giving a complete and exact count. Discontinuous measurement only samples behavior during set intervals, which is faster but gives an estimate rather than an exact count.
What are the 3 types of discontinuous measurement in ABA?
The three main types are partial-interval recording, whole-interval recording, and momentary time sampling. Each is chosen based on whether the goal is to increase or decrease a behavior, and how much time the observer has.
When should a therapist use discontinuous instead of continuous measurement?
Discontinuous measurement works well when a behavior happens too quickly or frequently to count in real time, or when a therapist is supervising multiple clients at once, such as in a classroom or community setting.
Does discontinuous measurement affect how accurate my child’s data is?
It can slightly over- or underestimate how often a behavior happens depending on the method used, but when applied consistently by a trained RBT, it still gives a reliable picture of progress over time.
3 Works Cited
-
1. Fiske, K. & Delmolino, L. (2012). Use of discontinuous methods of data collection in behavioral intervention: Guidelines for practitioners. Open source
-
2. LeBlanc, L. A., Lund, C., Kooken, C., Lund, J. B., & Fisher, W. W. (2020). Procedures and accuracy of discontinuous measurement of problem behavior in common practice of applied behavior analysis. Open source
-
3. Behavior Analyst Certification Board. (2021). RBT Handbook. Open source
