Introduction
The Chalder Fatigue Scale (CFS), developed in 1993 by Trudie Chalder and colleagues, is a cornerstone in psychological assessment for measuring the severity of physical and mental fatigue. Since its inception, this 14-item scale has garnered over 3,700 citations on Google Scholar, reflecting its widespread adoption in public health and psychiatry. Designed for adults aged 18 and older, the CFS is utilized in both clinical and community settings to screen, monitor, and inform treatment planning for fatigue-related conditions.
 This article provides researchers and clinicians with a comprehensive overview of the CFS, its applications, and its clinical value, ensuring actionable insights for effective fatigue assessment.
Key Features of the Chalder Fatigue Scale (CFS)
Purpose and Use
Published by the Department of Psychological Medicine, King’s College London, the primary purpose of the Chalder Fatigue Scale is to comprehensively assess the severity of fatigue, differentiating between its physical and mental manifestations. This instrument serves as a critical tool for screening, monitoring, and conducting research on fatigue-related conditions. Effectively, it helps practitioners identify individuals experiencing significant fatigue and track changes over time.
Target Population
The CFS is validated for adults across various age groups, including:
- Young Adults (18–24 years)
- Middle-Aged Adults (25–44 years)
- Older Adults (45–64 years)
- Seniors (65+ years)
It is particularly effective for populations experiencing chronic fatigue, such as those with chronic fatigue syndrome or post-viral fatigue.
Structure
The CFS is a 14-item scale divided into two sub-domains:
- Physical Fatigue (Items 1–8): Assesses symptoms like tiredness, low energy, drowsiness, muscle weakness, and the need for rest.
- Mental Fatigue (Items 9–14): Focuses on cognitive difficulties, including poor concentration, memory problems, slow thinking, and language slips.
These items collectively provide a comprehensive assessment of fatigue’s impact on both physical and mental functioning.
Scoring Method
The CFS offers two scoring methods, providing flexibility based on research or clinical objectives:
- Binary Scoring:
- “Better than usual” and “No more than usual” = 0
- “Worse than usual” and “Much worse than usual” = 1
- Total score range: 0–14
- Likert Scoring (This method provides greater granularity for assessing severity and change over time):
- 0 = Better than usual
- 1 = No more than usual
- 2 = Worse than usual
- 3 = Much worse than usual
- Total score range: 0–42
Researchers can strategically select the most appropriate scoring system, depending on whether their goal is screening for fatigue or monitoring its progression and response to interventions.
There are no official unified cut-off scores. However, in the original validation study, a binary score of ≥4 indicates significant fatigue, with a sensitivity of 75.5% and specificity of 74.5%.
Administration Format
The CFS is versatile and can be administered in multiple formats:
- Paper-based forms
- Digital (online) platforms
- In-person interviews
- Phone or video calls
It typically takes less than 5 minutes to complete, making it highly practical for busy clinical settings. Moreover, no specialized training is required, as the questionnaire is self-administered.
Applications of the Chalder Fatigue Scale (CFS)
The CFS is widely used in both clinical practice and research due to its robust design and psychometric properties. Key applications include:
- Screening: Quickly identifying patients with fatigue-related issues.
- Monitoring: Tracking patient progress during treatment or recovery.
- Research: Serving as a primary outcome measure in studies on chronic fatigue syndrome, post-viral fatigue, and related conditions.
For example, researchers often use the CFS in epidemiological studies to assess fatigue prevalence, while clinicians rely on it to tailor rehabilitation programs.
Languages and Availability
To ensure global accessibility, the CFS is available in several languages, including:
- English
- Mandarin Chinese
- Spanish
- Portuguese
- Japanese
And approximately 10 additional translations.
Reliability and Validity
The CFS is highly reliable and valid, with a Cronbach’s alpha ranging from 0.88 to 0.90, indicating excellent internal consistency. Its psychometric robustness has been confirmed through multiple validation studies, notably the original study by Chalder et al. (1993). This reliability makes the CFS a gold-standard tool for fatigue assessment across diverse populations.
Limitations and Considerations
However, despite its strengths, the Chalder Fatigue Scale has a few limitations:
- Self-report Measure: Responses may be influenced by social desirability bias or subjective interpretation.
- Narrow Focus (limited domains covered): The scale primarily assesses physical and mental fatigue, potentially overlooking other psychological or emotional factors.
- Lack of Unified Cut-off: While a binary score of ≥4 indicates fatigue, no universally standardized cut-off exists across all settings.
Cost and Licensing
The CFS requires permission from King’s College London for systematic use, adaptation, translation or redistribution under a proprietary license, but no specific cost is outlined for non-commercial use.
- For inquiries regarding the CFS-14 development and reuse, contact Professor Trudie Chalder at trudie.chalder@kcl.ac.uk.
- For general inquiries and licensing, contact King’s College London Intellectual Property & Licensing at innovation@kcl.ac.uk.
Other Versions and Related Questionnaires
Beyond the original 14-item Chalder Fatigue Scale (CFS-14), a revised 11-item version, the Chalder Fatigue Questionnaire (CFQ-11), was developed in 2010. This newer version aimed to enhance clarity, reduce redundancy, and improve internal consistency, and it is now widely utilized in clinical and research settings, but the original 14-item version remains commonly used in foundational studies.
For researchers exploring related constructs or seeking alternative measures, several other validated questionnaires are available. These include:
- FSS: the Fatigue Severity Scale.
- MFI: the Multidimensional Fatigue Inventory.
- the Piper Fatigue Scale.
Each offering unique perspectives on the multifaceted experience of fatigue.
Additional Resources
For further exploration, consider these resources:
- Access the original validation study here.
- Download the CFS questionnaire as a PDF (The full list of the 14 items included in the original scale is available in the appendix of the original validation study).
- For inquiries regarding the CFS-14 development and reuse, contact Professor Trudie Chalder at trudie.chalder@kcl.ac.uk.
- For general inquiries and licensing, contact King’s College London Intellectual Property & Licensing at innovation@kcl.ac.uk.
Frequently Asked Questions (FAQ)
- Who can use the Chalder Fatigue Scale?
Clinicians, researchers, and healthcare providers use the CFS for adults aged 18 and older, particularly those with fatigue-related conditions. - How long does it take to complete the CFS?
The questionnaire typically takes less than 5 minutes to complete, ensuring efficiency in clinical and research settings. - How is the CFS administered?
It can be administered via paper-based forms, digital platforms, in-person interviews, or phone/video calls, offering flexible options. - Is there any cost to using the CFS?
King’s College London retains copyright over the text and distribution of the questionnaire. Therefore, any systematic use, adaptation, translation, or redistribution requires their formal permission, and potential payment may be necessary.
A word from ResRef about the Chalder Fatigue Scale (CFS)
This instrument was launched in 1993 with 14 items under the name Chalder Fatigue Scale (CFS-14), and then developed in 2010 into a cleaner and more reliable version consisting of 11 items under the name Chalder Fatigue Questionnaire (CFQ-11).
References
- Chalder T, Berelowitz G, Pawlikowska T, Watts L, Wessely S, Wright D, Wallace EP. Development of a fatigue scale. J Psychosom Res. 1993;37(2):147-53. doi: 10.1016/0022-3999(93)90081-p. PMID: 8463991. Study link.
