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Posts by Michael Marks

Think would need to be very large (many agents, would need tight control for error at trial level, would need tight NI margins).

I guess my a priori belief isn't strong enough to want to invest limited trial budget in such study. If you could embed in EHRs & do very cheap might be more plausible.

1 day ago 0 0 1 0

MAMS-ROCI in Bayesian trials is being discussed in the context of SNAP (with @matteoq21.bsky.social).

For the de-escalation Q I think sample size to detect a meaningful difference in a mortality outcome between individual drugs would be very big & isn't where I would invest my trial budget.

1 day ago 3 0 1 0

These designs are (normally) informed by simulations to understand trial operating characteristics & each piece you add makes those more complex.

So have to decide which trade-offs to take. For example 7 days less Abx is a big reduction. Not sure knowing it could really have been 8 matters as much?

1 day ago 1 0 1 0

Adding a PRACTical design again would increase sample size and you would need a strong a-priori reason I think to consider that there are important enough differences between say amoxicillin and cefelexin.

1 day ago 1 0 1 0

I think there are other considerations. First complexity of randomisation & trial in general. Secondly to date I think MAMS-ROCI has only been evaluated in a frequentist framework & methods would need adapting for a bayesian trial. Although overall efficient it would also increase sample size.

1 day ago 1 0 1 0

Agree to disagree. In statistical terms I don't disagree of course. But in reality 1) how often these differences are meaningful is unclear to me 2) think much larger unsalvageable errors are in study design & therefore I'm less convinced of the need to be so strict from a pure "stats perspective"

3 days ago 0 0 1 0

Maybe. My general feeling is that outside of a few very clear issues it would be really hard to actually develop a protocol for this (although AI could possibly do this) AND I would want to see stronger evidence it mattered enough at a real-world level.

3 days ago 2 0 1 0

Yes although it shifts the burden to the also unpaid editor.

3 days ago 0 0 1 0

Sure. Toms point was that an editor should desk reject anyone who has dichotomised a variable. My point is that you might have variables that are effectively dichotomised like age into 'in the age group affected by policy or not' and so its not realistic to have a blanket policy of rejecting.

3 days ago 2 0 1 0
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I'd like to see (?simulations) better data on how often some of these practices lead to importantly wrong public health conclusion i.e age as continuous with a spline is more 'accurate' than groups but given how most policies are rolled out, under what circumstances does approach actually matter.

3 days ago 1 0 1 0

Its a great idea but I think its unrealistic.

I would also be concerned it would have negative equity impacts for authors from global south who have often less access to the level of statistical support required to meet the types of requirements being asked for.

3 days ago 2 0 1 0

Sure. But my point is that saying editors can just desk reject things if there someone dichotomises a continuous variable is not actually easy to implement. And I can definitely think of scenarios where there is no biological effect on an outcome only a policy level effect.

3 days ago 0 0 1 0

One issue is some of the rules are hard to apply in reality.
Age is continuous but say I am studying something related to pregnancy where the key external contextual factor is that people <18 are treated different than those of 18+. I think it would be reasonable to dichotomise age.

3 days ago 0 0 2 0

That said - I suspect we agree really.
I do agree that often Nil > Crap (my view from time to time of the GBD studies) - and I agree the trial design you describe is very difficult and often done badly - but I guess I think can be done well and is then helpful!

5 days ago 1 0 1 0

Does that mean all trials meet these criteria - No.
Does it mean these trials are harder than trials with a blinded intervention and an objective outcome like mortality - Yes.

But I disagree with your original suggestion that we can never trust such trials & therefore simply shouldn't do them.

5 days ago 1 0 1 0

I can not conceptualise a plausible natural experiment for Q 'Does CBT improve lived experience of depression'. I dont believe observational data can help nor 'expert opinion'

So my view is we do need well done trials & such trials can be done bearing in mind the issues highlighted.
3/n

5 days ago 1 0 1 0

You suggest we find alternative approaches or other solutions.
But
i) the meaningful outcome measures for many mental health conditions is by their nature the self-reported experience of the person
ii) most of these interventions cant be blinded
2/n

5 days ago 1 0 2 0

My view is you can do trials where a) unblinded b) plausible people know hypothesis & c) outcome subjective AND that those trials still generate good quality evidence.

i.e I think these trials (when done well) can generate non-misleading evidence & that is strongly preferable to no evidence.
1/n

5 days ago 1 0 1 0

Strong disagree. I think that these trials can (and have) been done robustly with results that are not misleading.

The approach you seem to advocate would mean we would never develop any good quality evidence at all on if behavioural interventions work for many mental health conditions.

5 days ago 0 0 1 0
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Does this really mean you think it would be better if we had done no trials of cognitive behavioural (or equivalent) therapy?

In some areas, especially mental health, THE outcome is self-reported symptomatology and I struggle to see how we would ever build evidence if we followed this suggestion.

5 days ago 0 0 1 0
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3 weeks ago 5 8 0 0

I think this differs hugely by discipline. For example in trials & much of clinical epidemiology, Introduction > Methods > Results is massively preferable as it provides a clear statement of the planned study & analysis which by its nature should have 95%+ been planned in advance.

1 week ago 3 0 1 0
Inequalities in infectious disease dynamics symposium | LSHTM Join us for the Social Inequalities in Infectious Disease Dynamics Symposium at the London School of Hygiene & Tropical Medicine (LSHTM). The day features a full programme of presentations and invited

Great symposium @lshtm.bsky.social on 22nd April.
Focused on analysis of social inequalities in transmission dynamics for infectious diseases.

Can join online or in person

(if coming in person please reach out to @rozeggo.bsky.social so we can make sure we have in-person capacity)

1 week ago 0 0 0 0
Job Opportunity at LSHTM: Clinical Research Fellow The London School of Hygiene & Tropical Medicine (LSHTM) is one of the world’s leading public health universities. Our mission is to improve health and health equity in the UK and worldwide; working in partnership to achieve excellence in...

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1 week ago 7 7 0 0
Job Opportunity at LSHTM: NIHR Clinical Lecturer in Primary Care/ General Practitioner The London School of Hygiene & Tropical Medicine (LSHTM) is one of the world’s leading public health universities. Our mission is to improve health and health equity in the UK and worldwide; working in partnership to achieve excellence in...

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3 weeks ago 0 2 0 0
2026-27 NIHR UK Syphilis Research Scholarship | LSHTM The London School of Hygiene and Tropical Medicine (LSHTM) is pleased to invite applications for a 3-year full-time PhD studentship, starting in September 2026.The award will cover a tax-free stipend

Do you have a background in Health Economics and want to come and do a PhD on Syphilis and STI

We have a funded studentship @lshtm.bsky.social. Come and collaborate with a great group of academics, clinicians and community groups

Open to people eligible for UK PhD Fee Status - Apply by 11th May.

3 weeks ago 5 8 0 0
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UKHSA Syphilis Response Plan

Really pleased to have contributed to the new @ukhsa.bsky.social Syphilis Action Plan and great to see this developed with a clear equity lens underpinning it.

A lot work required by a wide range of stakeholders to meet the ambition of this plan over the coming years.

3 weeks ago 6 1 0 0
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Double-dose azithromycin mass drug administration, facial cleanliness, and fly control measures for trachoma control in Oromia, Ethiopia (Stronger SAFE): a cluster-randomised controlled trial Enhanced A, F, and E (Stronger SAFE) had no additional effect compared with standard of care on reducing the prevalence of conjunctival C trachomatis at 3 years in this setting. It is therefore unlike...

New Research

Double-dose azithromycin mass drug administration, facial cleanliness, and fly control measures for trachoma control in Oromia, Ethiopia (Stronger SAFE): a cluster-randomised controlled trial

www.thelancet.com/journals/lan...

3 weeks ago 3 4 0 4
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3 weeks ago 8 7 0 0

For me the key take home from our recent work on African Syphilis genomics. Macrolide resistance now firmly established in South Africa & guidelines need to change & reflect this.

Great collaboration with colleagues @sangerinstitute.bsky.social & in South Africa, Zimbabwe, Botswana, Uganda & Ghana.

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