Tier 3 · Intensive

Functional behavior assessment (FBA)

A team process to figure out why a behavior happens by gathering interviews, observations, and data.

Setup: 2–4 weeks Who: School team, family

How to do it

  1. Form a team: teacher, family, administrator, and a behavior specialist or school psychologist.
  2. Define the target behavior clearly and measurably.
  3. Gather information: records review, teacher and family interviews, and student interview when appropriate.
  4. Collect direct observation data (ABC logs) across several settings and days.
  5. Look for patterns: when, where, with whom, and what happens after.
  6. Write a hypothesis statement: “When [trigger], [student] will [behavior] in order to [function].”
  7. Use the hypothesis to build a behavior intervention plan.

Why it works

  • Interventions that match the function of behavior work far better
  • Replaces guesswork with evidence
  • Required in many situations for students with disabilities

When to use it

  • Behavior is persistent despite Tier 1 and Tier 2 supports
  • Behavior is dangerous or seriously disrupts learning
  • When required by special education procedures or school policy

Tips and pitfalls

  • Follow your school’s procedures and consent requirements.
  • Look for “setting events” too: sleep, hunger, medication changes, conflicts at home.
  • An FBA is only useful if it leads to a plan.

Templates for this strategy

FBA interview and summary

Structured interview questions and a summary page with a hypothesis statement for a functional behavior assessment.

FBA interview and summary.docx

ABC observation log

Record what happened before, during, and after each incident to find patterns and the likely function of the behavior.

ABC observation log.docx

Frequency tally sheet

Count how often a behavior happens each day and period. Good for behaviors with a clear start and end, like calling out or hitting.

Frequency tally sheet.docx

On-task interval recording

Check whether the student is on task at regular intervals to measure engagement. Includes a peer comparison row.

On-task interval recording.docx

Helps with