Diagnostic Data

Diagnostic Data

When a student fails to respond to a validated intervention, teams need to identify why the student is not responding to determine how to adapt the intervention. Diagnostic data can assist teams in this process. They may be used to understand a student’s specific skill deficits and strengths or to identify the environmental events that predict and maintain the student’s problem behavior.

Diagnostic data may be collected through various formal and informal approaches. These may include standardized tools available through publishers; more informal approaches, such as error analysis of frequent progress monitoring data; or review of class assessments and work samples. In the behavior domain, diagnostic assessment occurs through functional behavioral assessment (FBA). In addition to this in-depth process, teachers also may use more informal measures and checklists to identify the function of the behavior. Other sources of diagnostic data may include feedback from parents, teachers, and others who work with the student.

Educators use diagnostic data to develop a hypothesis about the potential cause(s) of the student’s academic and/or behavioral difficulties. This hypothesis drives the team’s decisions about how best to support the student and adapt the intervention. For example, a team might use the behavioral data collected to alter variables that predict or maintain the student’s problem behavior (i.e., change or eliminate events that trigger or follow problem behavior), and promote more adaptive and acceptable skills that allow the student to appropriately access desired outcomes.

Find Additional Resources

Intervention Adaptation


Start with informal and easily accessible diagnostic data to prevent lost instructional time. These types of data sources are readily available in most classrooms.