Global Assessment of Functioning (GAF) Score Ranges

The GAF is a 100-point clinician-rated scale measuring overall psychological, social, and occupational functioning. Introduced in DSM-III-R (Axis V); widely used in clinical documentation, treatment planning, and insurance. Retained in DSM-IV and DSM-IV-TR. The anchor text is © American Psychiatric Association; licensing terms apply.

What the GAF measures

The GAF (Global Assessment of Functioning) is a clinician-administered rating scale that assesses an individual's overall level of psychological, social, and occupational functioning on a hypothetical continuum from severe impairment to superior functioning. It was developed for the DSM-III-R (1987) as Axis V and was a required component of DSM-IV multiaxial diagnosis. The scale ranges from 1 to 100, divided into 10-point anchor bands.

The GAF is designed to exclude impairment due to physical or environmental limitations, it rates only psychological, social, and occupational functioning. A clinician provides a single score by identifying the band that best describes the patient's lowest level of functioning in the past week. Scores of 50 or below indicate serious to severe impairment requiring clinical intervention. GAF scores are used extensively in treatment planning, progress notes, insurance documentation, disability determinations, and research.

The GAF was removed from DSM-5 (2013) in favour of the WHODAS 2.0 (World Health Organization Disability Assessment Schedule), which measures functioning across six specific life domains. Despite this change, the GAF remains widely used in clinical practice, electronic health records, and insurance systems. The GAF anchor text is © American Psychiatric Association; licensing terms apply.

How to administer the GAF

The GAF is clinician-administered. A trained mental health professional or physician assigns a single score from 1 to 100 based on clinical observation, interview and collateral information; it is not a questionnaire and cannot be self-scored. The clinician identifies the 10-point anchor band that best describes the patient's lowest level of functioning in the past week, excluding impairment due to physical or environmental limitations. Even brief rater training can yield satisfactory reliability (Jones et al., 1995).

Educational reference only. The GAF is a clinician-assigned rating, scores must be determined by a licensed mental health professional or physician.

GAF scoring and interpretation

DSM-IV (APA, 1994) and DSM-IV-TR (APA, 2000), Axis V. Clinician rates the lowest level of functioning during the past week. Exclude impairment due to physical or environmental limitations. The score reflects psychological, social, and occupational functioning only.

The score interpreter above lists the ten 10-point anchor ranges (1-10 through 91-100, plus 0 for inadequate information) as short paraphrases; the full anchor descriptions are in DSM-IV-TR (APA, 2000).

What does a GAF score of 50 mean?

A GAF of 50 sits at the top of the 41-50 band, which describes serious symptoms or serious problems at work, school or in relationships. Because the clinician rates the LOWEST level of functioning in the period, a single score reflects the worst functioning observed, not an average.

GAF vs. WHODAS 2.0

DSM-5 (2013) replaced the GAF with the WHODAS 2.0 for greater cross-cultural validity and alignment with the ICF (International Classification of Functioning). However, the GAF continues to be required by many insurers, EHR systems, and state mental health agencies. The GAF anchor text is © American Psychiatric Association; the WHODAS 2.0 is © World Health Organization. Check the copyright holder's terms before clinical or commercial use.

Psychometric properties

The GAF was adapted from the Global Assessment Scale (GAS), which showed good reliability across five studies, greater sensitivity to change than other overall severity ratings, and predicted hospital readmission for former inpatients rated below 40 (Endicott et al., 1976). In 103 patients with severe mental illness rated monthly for 6 months, total, symptom and disability GAF scores showed satisfactory reliability and were associated with support needs (Jones et al., 1995). In 432 outpatients with major depressive disorder, however, clinician and test-nurse ratings correlated only weakly (r = 0.26), indicating poor inter-rater reliability in routine practice (Grootenboer et al., 2012). In child and adolescent psychiatry, GAF reliability has ranged from fair to substantial depending on raters, training and diagnostic group (Schorre & Vandvik, 2004).

Limitations

• Not a diagnosis. The GAF reflects overall functional severity and does not diagnose any condition.
• Rater dependence. Reliability varies with rater training and setting; routine-practice inter-rater agreement can be poor (Grootenboer et al., 2012).
• Symptoms and disability combined. A single score mixes symptom severity with functioning, one reason DSM-5 moved to the WHODAS 2.0.
• Lowest level only. The score reflects the worst functioning in the period, not an average.

Measurement-Based Care in HiBoop

HiBoop does not offer the GAF; this page is reference material. HiBoop supports measurement-based care with the scales it offers, such as the PHQ-9, GAD-7 and PCL-5; see the assessment library.