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CGI Calculator
Clinical Global Impression Scale
A 2-item clinician-rated scale: illness severity (CGI-S) and global improvement (CGI-I). The most widely used brief assessment of the clinician's view of a patient's global functioning. Each item is read against its own anchor labels.
Score the CGI
Clinical scoring tool for practitioners. Enter observations to calculate the score.
- 2 items
- ~2 minutes
- Score range: 0–14
No data stored. Scoring happens in your browser.
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What is the CGI?
The Clinical Global Impression (CGI) scale is a brief clinician-rated measure that captures the clinician's overall impression of a patient's illness severity and treatment response. Developed by the US National Institute of Mental Health (NIMH) in 1976, it is one of the most widely used outcome measures in psychiatric clinical practice and research.
The CGI is used as two components: CGI-Severity (CGI-S) and CGI-Improvement (CGI-I). Each provides a global clinician rating that complements more detailed symptom-specific measures. (The original ECDEU manual also defined an Efficacy Index, a therapeutic-effect × side-effect matrix that is rarely used in modern practice and is not included here.)
How CGI Scoring Works
CGI-Severity (CGI-S): Rated 1-7 from "Normal, not at all ill" to "Among the most extremely ill patients."
CGI-Improvement (CGI-I): Rated 1-7 from "Very much improved" to "Very much worse" compared to baseline.
Each item is read against its own anchor labels and is not summed into a composite. The CGI is inherently subjective — it relies on the clinician's total clinical experience with the patient population to calibrate their ratings. This is both its strength (holistic assessment) and limitation (inter-rater variability).
Use the CGI inside Grounded Scribe
Registered practitioners can administer the CGI to clients, track scores across sessions, and auto-document results into clinical notes.
- Send to clientsEmail, SMS, or secure link.
- Track progress over timeOutcome charts and trend overlays.
Clinical Applications
The CGI is used across all areas of psychiatry and mental health. It is a standard outcome measure in clinical trials, a routine clinical tool for documenting treatment response, and a practical way to communicate patient status between clinicians.
Because it requires only a single global rating per component, it adds minimal burden to clinical encounters while capturing the clinician's overall clinical judgement.
CGI in Australian Practice
The CGI is used in Australian psychiatric services, clinical trials, and mental health outcome monitoring. It complements more detailed instruments like the BPRS, HoNOS, and specific symptom measures.
As a US federal government work (NIMH, 1976), the CGI is in the public domain and requires no permission or licensing for use.
Frequently Asked Questions About the CGI
Is the CGI free to use?
Yes. The CGI is a US federal government work (NIMH, 1976) and is in the public domain. No permission is required.
How should I calibrate my CGI ratings?
Rate based on your total clinical experience with the particular patient population. The CGI is designed to reflect clinical judgement, not a formula. Consistency comes from the clinician's familiarity with their patient group.
Can the CGI subscales be used independently?
Yes. The CGI-S (Severity) and CGI-I (Improvement) are frequently used as standalone measures, each read against its own anchor labels rather than combined.
See automated scoring inside Grounded Scribe →Related Clinical Calculators
Other validated instruments commonly used alongside the CGI.
- BPRS
Psychiatric MonitoringAn 18-item clinician-rated scale for assessing the severity of psychiatric symptoms including psychosis, mood disturbance, and anxiety.Calculate → - AIMS
Psychiatric MonitoringA 12-item clinician-rated scale for assessing tardive dyskinesia and other abnormal involuntary movements in patients taking antipsychotic medication.Calculate →
References
- Guy W. ECDEU Assessment Manual for Psychopharmacology — Revised. US Dept Health, Education, Welfare publication (ADM) 76-338. Rockville, MD: NIMH, 1976:218-222.
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