The IISCA: A Faster Functional Analysis

The IISCA is a short, focused way to test why a behavior happens. The letters stand for interview-informed synthesized contingency analysis. Many people also call it the ISCA for short.

It grew out of the standard functional analysis, a test of why behavior happens. BCBAs use it to plan safer, faster treatment. This page explains how it works and why clinicians like it.

What makes it an IISCA#

Dr. Joshua Jessel created the term for a specific test. It is the last stage of a larger practical assessment. He gives it its own name for a reason.

The final stage is the functional analysis, which has earned its own special term, the ISCA, or the interview informed synthesized contingency analysis. From the talk — Dr. Joshua Jessel

The design is simple on purpose. You use one test condition, not many. You compare it to a matched control condition.

What defines the functional analysis as the ISCA is that it includes a single test condition in which the individualized contingency informed by the open-ended interview and observation is compared to the non-contingent delivery of those same reinforcers in the matched control. From the talk — Dr. Joshua Jessel

The word "reinforcers" means things that make a behavior more likely. In the test, you give them only after the behavior. In the control, you give them freely.

The two conditions are matched on purpose. The only real difference is when the child gets the reward. If the behavior spikes in the test and not the control, you have your answer. That clean contrast is what makes the result trustworthy.

Built from a caregiver interview#

The "interview-informed" part is key. You start by asking the people who know the child. Their answers shape the whole test.

This is why the test fits real life so well. You are not guessing at causes in a lab. You build the exact situation the family described. That makes the plan match the child's true world.

It is fast#

Speed is a big reason clinicians choose it. A standard functional analysis can take hours. Jessel reports that the IISCA is much quicker.

If I come back to this review and add the data from the 127 ISCA's in the literature at the time, you can see that the ISCA only required a mean of 30 minutes to conduct. From the talk — Dr. Joshua Jessel

Thirty minutes is a huge savings. Less time in test means less time evoking hard behavior. That is safer for the child and the staff.

A real strength for feeding cases#

Dr. Holly Gover uses the IISCA in feeding work. She says it is one of the easiest tests to run there. The reasons are already known before you start.

An ISCA with a feeding issue is one of the easiest you can run because your EO is already identified and your reinforcers are pretty much identified. From the talk. Dr. Holly Gover

The "EO" means the establishing operation, or what makes something worth wanting right now. In feeding, the child often wants to escape a hard bite. A preferred food is the clear reward.

From assessment to treatment#

The IISCA does not stop at answers. It points straight to a treatment plan. Matt Harrington uses it as the front door to skill-based treatment.

Let's consider the ISCA as a small case example. This is undoubtedly one of the most efficient and most ecologically relevant functional analysis formats that we have at our disposal. From the talk. Matt Harrington

"Ecologically relevant" just means it matches real life. From the results, teams teach a functional communication response, a taught way to ask. Then they teach the child to wait when the answer is no. You can watch Matt work through a full case in Confessions of a New Behavior Analyst in Functional Analysis.

Why clinicians choose the IISCA#

The IISCA solves a few real problems at once. A standard test can take a long time to run. Long tests keep hard behavior going for longer. That is stressful for the child and risky for staff.

The IISCA cuts that time way down. It uses one clear condition drawn from an interview. So you spend less time evoking the behavior you fear. You still get a solid answer about what drives it.

It also flows straight into a plan. The same reinforcers you found become part of treatment. You teach the child a better way to reach them. The test and the treatment fit together like two halves.

There is a trade-off worth naming. The IISCA blends several possible causes into one condition. Some clinicians want to tease those causes apart. The choice depends on the case and the question you have.

What the research says#

The IISCA has a growing base of studies behind it. One review looked at the method across 17 studies. It reported strong efficiency and effectiveness across many settings and behaviors (Coffey, Shawler, Jessel, Nye, Bain, & Dorsey, 2019, Behavior Analysis in Practice).

Newer work adds a trauma-informed version. A two-step validation tested a performance-based IISCA in a single session. It aimed to avoid escalation and reduce harm during assessment (Jessel, Fruchtman, Raghunauth-Zaman, Leyman, Lemos, Val, Howard, & Hanley, 2023, Behavior Analysis in Practice). A later replication used it with three children with dangerous behavior. The matched treatment eventually eliminated that behavior and taught new skills (Fruchtman, Jessel, Pan, McLeod, & Rajaraman, 2025, Behavior Analysis in Practice).

The method also fits a long history of research. One review traced functional analysis over many decades. It named the practical, interview-informed approach as a leading modern option (Suchowierska-Stephany, 2024, Advances in Psychiatry and Neurology). The IISCA is new, but it stands on solid ground.

Support for practitioners keeps growing too. One study taught behavior analysts to build IISCA procedures. A short round of skills training raised their accuracy a lot (Metras, 2017, Teaching Behavior Professionals to Use the Interview-Informed Synthesized Contingency Analysis). This shows the method can be learned and used well in practice.

FAQ#

What is an IISCA? It is a brief functional analysis built from a caregiver interview. It uses one test condition and one matched control. The goal is to find why a behavior happens, fast and safely.

How is the IISCA different from a standard functional analysis? A standard test uses several separate conditions and can take hours. The IISCA uses a single, personal condition drawn from an interview. Research reports a mean of about 30 minutes to run it.

Does the IISCA lead to treatment? Yes. The results point straight to a skill-based treatment plan. Teams teach a clear way to ask for what the child wants. Then they teach the child to tolerate waiting.