Scientific background: Functional Impairment
About this test
The WFIRS-S was developed by Margaret D. Weiss to complement pure symptom checklists like the ASRS-v1.1 with a question they don't answer: how much do these difficulties actually affect day-to-day functioning? A conceptual review (Weiss et al., 2018) summarizes that symptom improvement doesn't automatically track with functional improvement -- the two are related but distinct. The WFIRS-S has been translated into 18 languages and psychometrically evaluated in student and adult samples in the US, Japan, and Iran, among others, with consistently good internal consistency. Unlike the parent-report version (WFIRS-P), no study to date has established a validated cutoff for the self-report form -- Weiss et al. (2018) explicitly name this as open research. What is available are reference means from individual samples (e.g. Canu et al., 2016: adult students screening positive for ADHD, M=0.88; screening negative, M=0.35). Official scoring uses the mean per domain, not the sum, so items marked "not applicable" don't distort the calculation.
Canu and colleagues' 2016 study, in a very large sample of 2,093 college students, reports exceptionally high internal consistency (Cronbach's alpha above .96 for both self-report and informant-report) and good agreement between the two report forms. The same study also found an important caveat: measured impairment correlated not only with ADHD symptoms but also with internalizing symptoms like anxiety and low mood. The WFIRS-S measures general everyday impairment, not ADHD-specific impairment -- an elevated score can have causes other than ADHD.
Dimensions
Total score
Mean across all 69 items you didn't mark "not applicable."
Family
Impact on your relationship and family life (8 items).
Work
Impact on duties, teamwork, and your job (11 items).
School
Impact on school, college, or training (10 items).
Life Skills
Everyday routines like sleep, nutrition, appearance, chores, and money (12 items).
Self-Concept
How satisfied and competent you feel about yourself (5 items).
Social
Friendships, cooperation, and getting along with others (9 items).
Risky Activities
Rare but potentially consequential behaviors like risky driving or substance use (14 items).
Sources & license
Weiss, M. D. Weiss Functional Impairment Rating Scale -- Self-Report (WFIRS-S).
© Margaret D. Weiss. The scale is copyrighted by Margaret Danielle Weiss, MD PhD and, per the form's own footer, "can be used by clinicians and researchers free of charge and can be posted on the Internet or replicated as needed." Used here under that same standing permission already confirmed with Dr. Weiss for empiralis.de's non-commercial use of the German translation (margaret.weiss@icloud.com). No commercial redistribution without separately checking back with the author.
https://www.caddra.ca/wp-content/uploads/WFIRS-S.pdfCanu, W. H., Hartung, C. M., Stevens, A. E., & Lefler, E. K. (2016). Psychometric properties of the Weiss Functional Impairment Rating Scale: Evidence for utility in research, assessment, and treatment of ADHD in emerging adults. Journal of Attention Disorders.
US college-student sample, source of the reference means (ADHD-positive M~0.88, ADHD-negative M~0.35).
Weiss, M. D., McBride, N. M., Craig, S., & Jensen, P. (2018). Conceptual review of measuring functional impairment: findings from the Weiss Functional Impairment Rating Scale. Evidence Based Mental Health, 21(4).
Open Access under CC BY-NC 4.0 -- source for the current state of WFIRS-S validation research.
https://doi.org/10.1136/ebmental-2018-300025CADDRA. Weiss Functional Impairment Rating Scale-Self (WFIRS-S) -- Scoring Guide.
© 2025 CADDRA, provided for private/clinic reference -- source for the official domain-level scoring rule (mean domain score, DSM-IV-based impairment rule) described in this test's own wording above, not reproduced verbatim.
https://adhdtreat.caddra.ca/wp-content/uploads/2025/01/Weiss-Functional-Impairment-Rating-Scale-Self-WFIRS-S%E2%80%93Scoring-Guide-1.pdf