Assessment & Research

Reliability and validity of the functional analysis screening tool.

Iwata et al. (2013) · Journal of applied behavior analysis 2013
★ The Verdict

A 16-item checklist gives a fast, fairly reliable guess at behavioral function and matches full analyses two-thirds of the time.

✓ Read this if BCBAs who run multiple FBAs each week in schools or clinics.
✗ Skip if Clinicians who already have strong interview data and always proceed straight to full FAs.

01Research in Context

01

What this study did

The team built a 16-question checklist called the Functional Analysis Screening Tool, or FAST.

Staff answer yes or no about attention, escape, sensory, and tangible items.

They then compared the checklist to full experimental functional analyses to see if the quick form guessed the real function.

02

What they found

FAST matched the full analysis about two-thirds of the time.

Different raters gave similar scores, so the tool is moderately reliable.

It is good enough to screen, but not to replace, a real functional analysis.

03

How this fits with other research

Katz et al. (2003) built an earlier checklist called the FACT for behaviors with many causes. FAST is simpler and focuses on one main function.

Jolliffe et al. (1999) showed that full functional analyses themselves can give different answers on different days. This helps explain why FAST is only 64 % accurate— the gold standard also wobbles.

McCabe et al. (2023) tried adding heart-rate monitors to FA and found no extra benefit. Like FAST, their work asks: what is the leanest way to get valid data?

04

Why it matters

You can hand the FAST to a teacher or parent, get a quick read, and decide if a full FA is worth the time. When answers line up, you save hours. When they clash, you know to dig deeper. Keep the form in your clipboard for Monday morning triage.

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→ Action — try this Monday

Print the FAST, give it to the teacher, and let the score guide whether you schedule a full functional analysis this week.

02At a glance

Intervention
functional behavior assessment
Design
other
Sample size
196
Population
not specified
Finding
positive
Magnitude
medium

03Original abstract

The Functional Analysis Screening Tool (FAST) is a 16-item questionnaire about antecedent and consequent events that might be correlated with the occurrence of problem behavior. Items are organized into 4 functional categories based on contingencies that maintain problem behavior. We assessed interrater reliability of the FAST with 196 problem behaviors through independent administration to pairs of raters (Study 1). Mean item-by-item agreement between pairs of raters was 71.5%. Agreement for individual items ranged from 53.3% to 84.5%. Agreement on FAST outcomes, based on comparison of informants' highest totals, was 64.8%. We assessed the validity of the FAST by comparing its outcomes with results of 69 functional analyses (Study 2). The FAST score predicted the condition of the functional analysis in which the highest rate of problem behavior occurred in 44 cases (63.8%). Potential uses of the FAST in the context of a clinical interview, as well as limitations, are discussed.

Journal of applied behavior analysis, 2013 · doi:10.1002/jaba.31