Weiss Functional Impairment Rating Scale — Self-Report (WFIRS-S)
Measures how ADHD symptoms affect daily functioning across 7 life domains.
Last reviewed: May 2026
The WFIRS-S was developed by Margaret Weiss to measure functional impairment specifically associated with ADHD. Unlike symptom scales (which ask "how often"), the WFIRS-S asks "how much does this affect your life.
Scoring & Interpretation
Each item scored 0 (Never) to 3 (Very Often). Domain scores are mean of non-missing items within that domain. Total score is mean of all items. Higher scores = greater impairment. Items endorsed as 2 or 3 are considered "clinically impaired" for that area.
| Score Range | Severity | Clinical Action |
|---|---|---|
| 0.0–0.5 | Minimal impairment | Functioning within normal limits |
| 0.5–1.0 | Mild impairment | Monitor — may benefit from support strategies |
| 1.0–1.5 | Moderate impairment | Impairment consistent with ADHD diagnosis |
| 1.5–2.0 | Severe impairment | Significant functional impact — treatment priority |
| 2.0–3.0 | Very severe impairment | Major life disruption — urgent intervention |
Internal consistency: Cronbach's α = 0.95 (total), 0.80–0.93 (domains). Test-retest reliability: ICC = 0.85. Discriminates ADHD from healthy controls (d = 1.3–1.8 across domains). Sensitive to treatment change in medication trials (Weiss et al., 2018). Validated in 12 countries.
When to Use This vs Alternatives
Use ASRS when…
You need to screen for ADHD symptoms (frequency), not measure impairment. The ASRS asks "how often do you have trouble concentrating?" — the WFIRS-S asks "how much does poor concentration affect your work, relationships, and daily life."
View ASRS →Use ADHD-FIS when…
You want a much briefer functional impairment measure (6 items, 2 minutes). The ADHD-FIS gives a quick snapshot; the WFIRS-S gives a comprehensive 7-domain profile. Use ADHD-FIS for routine monitoring, WFIRS-S for initial assessment.
View ADHD-FIS →Use ACOS when…
You want to track overall ADHD symptom severity as an outcome over time rather than functional impairment. The ACOS gives a brief symptom-and-impact total; the WFIRS-S maps impairment across seven life domains.
View ACOS →See It in Action
- 1Mean impairment score with severity band
- 2Individual question responses with scoring badges
- 3Clinical note on interpretation
- 4One-click PDF export and email delivery
What It Measures
The WFIRS-S was developed by Margaret Weiss to measure functional impairment specifically associated with ADHD. Unlike symptom scales (which ask "how often"), the WFIRS-S asks "how much does this affect your life." It covers 7 domains: Family, Work, School, Life Skills, Self-Concept, Social, and Risk-Taking. This makes it essential for demonstrating that ADHD symptoms cause clinically significant impairment — a DSM-5 diagnostic requirement.
When to Use the WFIRS-S
Use the WFIRS-S after confirming ADHD symptoms are present (e. g., via ASRS screen). DSM-5 requires evidence of functional impairment for diagnosis. The WFIRS-S provides this evidence across multiple life domains. Also useful for treatment monitoring — track whether medication or therapy reduces real-world impact over time.
Who It's For
Adults and adolescents aged 16+. Self-report. Validated in clinical ADHD populations and community samples. Available in 18 languages. For children under 16, use the parent-report version (WFIRS-P).
Frequently Asked Questions
What does the WFIRS-S measure?
The WFIRS-S measures functional impairment caused by ADHD symptoms across 7 life domains: Family, Work, School, Life Skills, Self-Concept, Social, and Risk-Taking. It answers "how much does ADHD affect your daily life" rather than just measuring symptom frequency.
How do you score the WFIRS-S?
Each of the 69 items is rated 0 (never) to 3 (very often). Domain scores are the mean of the items in that domain and the total is the mean of all items, so scores range from 0 to 3. Items a patient rates 2 or 3 mark areas of clinically significant impairment.
What is a clinically significant WFIRS-S score?
Higher mean scores indicate greater impairment, and any item rated 2 or 3 flags an area of concern. A mean item score around 0.65 has been reported as a screening threshold rather than a diagnostic cut-off; the WFIRS-S documents the functional impairment DSM-5 requires for an ADHD diagnosis, which the psychologist interprets in context.
Why use the WFIRS-S alongside the ASRS?
DSM-5 requires both symptoms AND functional impairment for ADHD diagnosis. The ASRS confirms symptoms are present; the WFIRS-S documents that those symptoms cause real-world problems. Together they provide the full diagnostic picture.
Use the WFIRS-S in your practice
New accounts get 30 days of full Professional access, no card. After that it is on the Starter plan, with instant scoring, severity bands and PDF reports. Scored the moment patients submit.