Skip to content
DraconiticResearch
Search Sources API
201,818 studies31 sourcesUpdated 14 min ago
PreprintCC BYmedRxiv

The development and psychometric evaluation of the Post Activity Symptom Scale (PASS) for Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome.

  • M. Horton
  • S. F. Tyson1
  • R. Fleming
  1. 1University of Manchester.ac.uk
Read full textPDFDOICite

Abstract

Purpose: To develop and psychometrically evaluate a new scale measuring post-exertional malaise in people with myalgic encephalomyelitis (ME)/ chronic fatigue syndrome (CFS). Methods: A draft scale was co-produced with patient and clinician advisory groups. After extensive pilot testing, adults with ME/CFS completed the Post Activity Symptom Scale online and repeated it two weeks later to assess test-retest reliability and sensitivity to change. Rasch analysis assessed each domain for unidimensionality, targeting, internal reliability, item fit and local dependency. Then Rasch-transformed interval data and parametric statistics were used to assess criterion-related and discriminant validity (by comparison with measures of physical health and ME/CFS severity), test-retest reliability and minimal detectable difference. Results: The item regarding delay in PEM onset was an under-discriminating misfit anomaly which was inconsistent with the remaining PASS items. When this was removed, the PASS was a unidimensional, psychometrically robust scale. Criterion-related validity (r=0.58, p<0.001) was moderate and highly significant, discriminant validity (p<0.001) and test-retest reliability (ICC = 0.81) were excellent. The minimal detectable difference was 1.93/100. Participants found the PASS easy to complete, comprehensive and relevant. Conclusion: The Post Activity Symptom Scale is a valid, reliable, sensitive measure of people of PEM in ME/CFS

Related

  1. Development and psychometric evaluation of the Severity of Myalgic Encephalomyelitis Scale (SoMES) and the Myalgic Encephalomyelitis Occupational Status Scale (MEOSS)
    S. F. Tyson, R. Fleming
    medRxivPreprintCC BYFull textGeneral medicinemedRxiv
  2. Development and Preliminary Psychometric Evaluation of a Questionnaire on Comprehensive Protection, Quality, and Humanization in Pediatric Hospital Care
    Germán Rojas Loyola, Begoña Polonio-López, Juan José Criado-Alvarez +1
    Pediatric reportsPeer-reviewedCC BYFull textGeneral medicineEurope PMC
  3. Subjective word-finding complaints in older adults: Development and preliminary psychometric evaluation of a novel self-reported questionnaire
    F. El-Khaldi, A. Marier, P. Vitali +3
    medRxivPreprintAll rights reservedFull textPsychiatry & mental healthmedRxiv
  4. Development and Psychometric Evaluation of the AASPIRE Social Support Scale for Autistic Adults
    Wei Song, Todd C. Edwards, Mary Baker-Ericzén +9
    medRxivPreprintAll rights reservedFull textEpidemiology & public healthmedRxivPMC
  5. Development and psychometric evaluation of a pre-sarcopenia risk assessment scale for sedentary young adults with type 2 diabetes mellitus
    Chen-Xia Zhang, Cong-Cong Jin, Shi-Wei Liu +2
    Frontiers in Public HealthPeer-reviewedCC BY 4.0Epidemiology & public healthCrossref

Cite

BibTeXRIS
BibTeX
@misc{horton2026development,
  title = {{The development and psychometric evaluation of the Post Activity Symptom Scale (PASS) for Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome.}},
  author = {M. Horton and S. F. Tyson and R. Fleming},
  howpublished = {medRxiv},
  year = {2026},
  month = nov,
  doi = {10.64898/2026.11.06.26367424},
  url = {https://www.medrxiv.org/content/10.64898/2026.11.06.26367424v1},
  note = {CC BY},
}
RIS
TY  - UNPB
TI  - The development and psychometric evaluation of the Post Activity Symptom Scale (PASS) for Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome.
AU  - M. Horton
AU  - S. F. Tyson
AU  - R. Fleming
PY  - 2026
DA  - 2026/11/06
PB  - medRxiv
DO  - 10.64898/2026.11.06.26367424
UR  - https://www.medrxiv.org/content/10.64898/2026.11.06.26367424v1
AB  - Purpose: To develop and psychometrically evaluate a new scale measuring post-exertional malaise in people with myalgic encephalomyelitis (ME)/ chronic fatigue syndrome (CFS). Methods: A draft scale was co-produced with patient and clinician advisory groups. After extensive pilot testing, adults with ME/CFS completed the Post Activity Symptom Scale online and repeated it two weeks later to assess test-retest reliability and sensitivity to change. Rasch analysis assessed each domain for unidimensionality, targeting, internal reliability, item fit and local dependency. Then Rasch-transformed interval data and parametric statistics were used to assess criterion-related and discriminant validity (by comparison with measures of physical health and ME/CFS severity), test-retest reliability and minimal detectable difference. Results: The item regarding delay in PEM onset was an under-discriminating misfit anomaly which was inconsistent with the remaining PASS items. When this was removed, the PASS was a unidimensional, psychometrically robust scale. Criterion-related validity (r=0.58, p<0.001) was moderate and highly significant, discriminant validity (p<0.001) and test-retest reliability (ICC = 0.81) were excellent. The minimal detectable difference was 1.93/100. Participants found the PASS easy to complete, comprehensive and relevant. Conclusion: The Post Activity Symptom Scale is a valid, reliable, sensitive measure of people of PEM in ME/CFS
ER  -