Fatigue Severity Scale

FSS

health sciencespsychologyFree for research use

A 9-item unidimensional scale measuring the functional impact of fatigue on daily activities, developed in multiple sclerosis and lupus populations.

Items

Response format

7-point Likert, anchored strongly disagree to strongly agree

Version

1.0

Ready-to-cite methods sentence

Fatigue was measured with the Fatigue Severity Scale (FSS; Krupp et al., 1989), a 9-item measure with good internal consistency (α ≈ .88); a mean score of 4 or more indicates clinically significant fatigue.

Citing this in a methods section? This scale spans more than one discipline, so the style depends on where you publish — see the APA 7 or Vancouver guides, or compare all six citation styles.

Reliability & validation

Validation population

Multiple sclerosis and systemic lupus erythematosus patients (Krupp et al., 1989)

Cronbach's α

0.88

Known limitations

Developed in neurological and autoimmune populations, so norms may not transfer to healthy or psychiatric samples; it captures the impact of fatigue rather than its intensity or cause.

Original citation

Krupp, L. B., LaRocca, N. G., Muir-Nash, J., Steinberg, A. D. (1989). The Fatigue Severity Scale: Application to patients with multiple sclerosis and systemic lupus erythematosus. Archives of Neurology, 46(10), 1121-1123.

https://doi.org/10.1001/archneur.1989.00520460115022

Questions researchers ask

What does the FSS measure?

A 9-item unidimensional scale measuring the functional impact of fatigue on daily activities, developed in multiple sclerosis and lupus populations.

How many items does the FSS have?

The Fatigue Severity Scale (FSS) has 9 items.

Is the FSS free to use?

The FSS is free to use for non-commercial academic research. You don't need to pay a license fee, but you should always cite the original publication.

Is the FSS reliable?

Validation studies report Cronbach's α of 0.88. See the reliability section for the population studied and full statistics.

Who developed the FSS, and how do I cite it?

Reference only

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Library entry verified July 2026. Metadata is provided for reference; item wording is available inside Folio Surveyor, subject to each instrument's licensing.