Preprint Psychometric evaluation of The Index of Myalgic Encephalomyelitis Symptoms TIMES. Part II…, 2026, Tyson, Horton, Fleming

[SNT Gatchaman]

Psychometric evaluation of The Index of Myalgic Encephalomyelitis Symptoms TIMES. Part II: Criterion-related and discriminant validity, test-retest reliability and minimal detectable difference.

Spoiler: Authors

Sarah F Tyson; Mike C Horton; Russell Fleming

OBJECTIVE
To evaluate the criterion-related and discriminant validity, test-retest reliability and minimal detectable difference of The Index of ME Symptoms (TIMES) in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

METHODS
People with ME/CFS in the UK completed the TIMES online (n=1055). Rasch-transformed interval data and parametric statistics were used: Pearson correlations (with the ME severity scale); analysis of variance; intra-class correlations (ICC) and standard error of measurement of ICC measured criterion-related and discriminant validity, test-retest reliability and minimal detectable difference respectively.

RESULTS
Highly significant (P<0.001) moderate (r=0.400- 0.528) correlations were seen between the TIMES scales and severity of ME/CFS except the gastro-intestinal and immune systems scales (r= 0.315 and 0.302 P<0.001 respectively). Discriminant validity was demonstrated with significant differences in TIMES scores between all five levels of ME severity, except between levels 4 and 5 in some cases, which were underpowered due to the small group numbers. Test-retest reliability was excellent (ICC>0.7, p<0.001) except the cranial nerves and immune system scales which were good (ICC = 0.681 and 0.669, p<0.001) and minimal detectable difference was excellent (3.95-17.45%).

CONCLUSIONS
The Index of ME Symptoms (TIMES) scales are valid, reliable, sensitive assessments of symptoms in ME/CFS. They are freely available for use.

Web | DOI | PDF | Preprint: MedRxiv | Open Access

 

[SNT Gatchaman]

The domains excluding fatigue also form valid sub-scales which assess neurological symptoms and dysautonomia.

We commented in the thread for the first paper that it makes no sense to have cranial nerves in a dysautonomia section when neurology is right there. Also sleep and the immune system in dysautonomia ?!? (As well as dysautonomia relating to neurology anyway). Arbitrary and ill-informed.

The TIMES was co-produced with people with ME/CFS and clinicians working in specialist NHS ME/CFS services using the methods detailed in the companion paper. They are summarised here. An ME/CFS advisory group with a wide range of age, duration and severity of ME/CFS was convened from volunteers following publicity in the ME Association’s newsletter. Members of the clinical advisory group were drawn from volunteers from the membership of the British Association of Clinicians in ME (BACME). Both groups contributed to all stages of the project.

Spoiler: Content warning for crimes against graphic design

 

[Hutan]

"Spoiler: Content warning for crimes against graphic design"
you've got to laugh....

I have no idea why they had to spread this stuff over two papers. It seems to be repeating a lot of what was in the first paper, which mostly seems to be 'this is great, we did a fabulous job'.

And I repeat - one question on PEM and, what was it five or six? on aspects of sleep. This scale will make it relatively easy for rehab people to show they have achieved improvements when in fact they have not. 'Excessive farting'* could go from 3 points to zero points just by revising the person's understanding of how much farting is normal. PEM could genuinely go from mild frequency to moderate frequency and it wouldn't increase the score at all.

This scale is junk.

*yes, I am not joking, it is a symptom on the list


Here's the scale for easy access:
Supplementary file 4 is the TIMES final version. Attaching it here so that people can more easily acces it.

 

[hotblack]

I have no idea why they had to spread this stuff over two papers

So you can hit a measurable outcome of papers published for funds given?

 

[hotblack]

The Index of ME Symptoms (TIMES) scales are valid, reliable, sensitive assessments of symptoms in ME/CFS

No they are not. Like its predecessor the paper appears to overstate its value and use when all thot has been done is massage some numbers. There is no evidence this tells us anything about the real world or gives us biological insight given we have little to measure against. I’m not convinced the results are anything more than a product of mathematical modelling.

Comparing subjective things does not make them objectively valid. There’s a circular loop here, saying a subjective measure validates a subjective measure. Forcing messy human experience into a linear scale is never perfect, admit that to improve a questionnaire rather than pretend maths can make it true.

The repeatability shown could just as well mean this is not capturing variation or changes in the condition, which would be problematic for understanding the condition or effects of any interventions. We know people vary and yet this seems to either not be captured or been squeezed out of the model producing something which lacks sensitivity.

There seems to be questions over measuring severity and I won’t repeat my other concerns from the other paper. But I hope this gets solidly and critically peer reviewed, otherwise the authors will now promote it to say it does things it doesn’t with consequences on the community. What a waste from the MEA and entirely counterproductive to some of their other work and investments.

 

[Amw66]

We commented in the thread for the first paper that it makes no sense to have cranial nerves in a dysautonomia section when neurology is right there. Also sleep and the immune system in dysautonomia ?!? (As well as dysautonomia relating to neurology anyway). Arbitrary and ill-informed.

Spoiler: Content warning for crimes against graphic design

View attachment 30902

Coproduced ?
That's seems elastic interpretation given the discussions here and on the MEA Facebook page .

I wonder how much participation the patient advisory group had , and how much stats / methodology background they had .

 

[Amw66]

"Spoiler: Content warning for crimes against graphic design"
you've got to laugh....

I have no idea why they had to spread this stuff over two papers. It seems to be repeating a lot of what was in the first paper, which mostly seems to be 'this is great, we did a fabulous job'.

And I repeat - one question on PEM and, what was it five or six? on aspects of sleep. This scale will make it relatively easy for rehab people to show they have achieved improvements when in fact they have not. 'Excessive farting'* could go from 3 points to zero points just by revising the person's understanding of how much farting is normal. PEM could genuinely go from mild frequency to moderate frequency and it wouldn't increase the score at all.

This scale is junk.

*yes, I am not joking, it is a symptom on the list


Here's the scale for easy access:
Supplementary file 4 is the TIMES final version. Attaching it here so that people can more easily acces it.

" This scale will make it relatively easy for rehab people to show they have achieved improvements when in fact they have not"

Exactly this .
The King is dead , long live the King .

I think this needs a response akin to the BACME letter . This has the potential to do as much damage .