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With reference to the position in the pyramid of evidence, it is probably at the bottom, because it provides mainly bread and butter for the writers and the institution/university? Models are, I think, an indication to look for conflict of interest, to check for pharmaceutical industry interests, as these in turn push for governmental policies and at the WHO, favourable to the industry and people should also check grants made to universities? Following on from Hilda Bastians tweet https://twitter.com/hildabast/status/1257190416027250696?s=12 which refers to an article that states: "While in the past it was justifiable to err on the side of - substantially overestimating - flu deaths, in order to encourage vaccination and good hygiene" https://blogs.scientificamerican.com/observations/comparing-covid-19-deaths-to-flu-deaths-is-like-comparing-apples-to-oranges Flu vaccines are still going strong despite little evidence? https://annals.org/aim/article-abstract/2762506/effect-influenza-vaccination-elderly-hospitalization-mortality-observational-study-regression-discontinuity The credibility of public health organizations globally is on the line, when these on purpose, to enable policies, "substantially overestimate" flu deaths for example. This undermines public trust in modelling, assumptions and projections. The outcomes of these are probably to promote the utilitarian stance that results from the "intensive" international scientific collaboration between public health agencies under the coordination of the World Health Organization with the scientific community, the public health community, policymakers and influenza vaccine manufacturers. This alignment with the vaccine industry was stated by Penttinen and Friede in 2016. http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=22609 Wouter Havinga. locum GP, UK On Wed, May 6, 2020 at 10:43 AM Huw Llewelyn [hul2] <[log in to unmask]> wrote: > Hi Tom > > I basically agree with Kumar, Kev and Jon. I see the role of models as > connecting two types of evidence: the ‘general’ (graded using a pyramid) > and the ‘particular’ (eg belonging to the patient in front of me). > > A RCT provides ‘general‘ evidence in a selected population in the form of > an observed difference in data in the ( often in the form of proportions) > between intervention and control. There should also be data in the form of > continuous variables of severity displayed by each patient entered into the > RCT (eg individual BP levels or albumin excretion rate). > > A patient to whom this information is to applied will display ‘particular’ > evidence in the form of of a personal degree of severity (eg a BP level or > albumin excretion rate). > > In order to connect the ‘general’ RCT evidence to the ‘particular’ > individual patient’s evidence, we always need a model. This might be simple > based only by assuming that the individual patient was randomly selected > from those in the RCT. In my approach however, it will depend on an > assumption of constant odds ratio applied to to a range of baseline risks > derived from the control data. This is an example: > > > > https://www.semanticscholar.org/paper/The-scope-and-conventions-of-evidence%E2%80%90based-need-to-Llewelyn/e9745b3c3a14b84914d9bfdb85a91ad736704f98. > (Please note that Figures 3 and 4 have been transposed by whoever created > the semantic summary so that the legends belong to the wrong curves). > > > The context of these Figures is provided in the abstract, which ‘semantic’ > also shows. > > > Best wishes > > Huw > > On 6 May 2020, at 10:34, Jon Brassey <[log in to unmask]> wrote: > > > Hi Tom, > > Is it as simple as that? Systematic reviews are seen as the top (or near > the top) of the evidence pyramid - but are ALL systematic reviews the same? > We know they are not - so a poor systematic review (depending how bad it > is) is potentially junk and should be below, say, a single large, > well-conducted, RCT. > > Continuing in that thread, models range from good to bad(awful) and it's > context specific - no doubt depending on things like the complexity of the > situation you're trying to model, the available data etc. > > Having said all that - even if it was a good model - it doesn't feel right > to place it in the traditional EBM hierarchy as I'm not sure you're > comparing apples to apples! > > Cheers > > jon > > On Wed, 6 May 2020 at 10:27, Tom Jefferson <[log in to unmask]> > wrote: > >> Thanks Kumar. So Where would you position mathematical models in the >> piramid of evidence? >> >> Tom >> >> >> On Wed, 6 May 2020 at 11:20, K Hopayian < >> [log in to unmask]> wrote: >> >>> I wonder, do models use evidence rather than count as evidence? >>> >>> On 6 May 2020, at 08:48, Tom Jefferson <[log in to unmask]> wrote: >>> >>> Good morning all I have a question for the group: >>> >>> Where would you position mathematical models in the piramid of evidence? >>> >>> Thank you for your time >>> >>> Tom. >>> >>> >>> Dr Tom Jefferson >>> Senior Associate Tutor, University of Oxford >>> >>> Researcher, Nordic Cochrane Centre >>> Visiting Professor, Newcastle University >>> >>> >>> ------------------------------ >>> >>> To unsubscribe from the EVIDENCE-BASED-HEALTH list, click the following >>> link: >>> >>> https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=EVIDENCE-BASED-HEALTH&A=1 >>> <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.jiscmail.ac.uk%2Fcgi-bin%2Fwebadmin%3FSUBED1%3DEVIDENCE-BASED-HEALTH%26A%3D1&data=02%7C01%7C%7C118846187a3f4c43279208d7f1a0bcaa%7Cd47b090e3f5a4ca084d09f89d269f175%7C0%7C1%7C637243544976796732&sdata=sSPdX5L62hnS1BQXBEqLhEW%2Bh8sDmaTvgYKn2WoxM5w%3D&reserved=0> >>> >>> >>> >>> ------------------------------ >>> >>> To unsubscribe from the EVIDENCE-BASED-HEALTH list, click the following >>> link: >>> >>> https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=EVIDENCE-BASED-HEALTH&A=1 >>> <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.jiscmail.ac.uk%2Fcgi-bin%2Fwebadmin%3FSUBED1%3DEVIDENCE-BASED-HEALTH%26A%3D1&data=02%7C01%7C%7C118846187a3f4c43279208d7f1a0bcaa%7Cd47b090e3f5a4ca084d09f89d269f175%7C0%7C1%7C637243544976796732&sdata=sSPdX5L62hnS1BQXBEqLhEW%2Bh8sDmaTvgYKn2WoxM5w%3D&reserved=0> >>> >> >> ------------------------------ >> >> To unsubscribe from the EVIDENCE-BASED-HEALTH list, click the following >> link: >> >> https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=EVIDENCE-BASED-HEALTH&A=1 >> <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.jiscmail.ac.uk%2Fcgi-bin%2Fwebadmin%3FSUBED1%3DEVIDENCE-BASED-HEALTH%26A%3D1&data=02%7C01%7C%7C118846187a3f4c43279208d7f1a0bcaa%7Cd47b090e3f5a4ca084d09f89d269f175%7C0%7C1%7C637243544976806724&sdata=ysDqfqhs4R6btRBPjZ2oWA3DPAwqGOFLbk0xQV5Wrg8%3D&reserved=0> >> > > > -- > Jon Brassey > Director, Trip Database > <https://eur02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.tripdatabase.com%2F&data=02%7C01%7C%7C118846187a3f4c43279208d7f1a0bcaa%7Cd47b090e3f5a4ca084d09f89d269f175%7C0%7C1%7C637243544976806724&sdata=x9tggBh5UESKntHJGOQw29JoY%2F7LzL8APYjXV5dfMgA%3D&reserved=0> > Honorary Fellow at CEBM > <https://eur02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.cebm.net%2F&data=02%7C01%7C%7C118846187a3f4c43279208d7f1a0bcaa%7Cd47b090e3f5a4ca084d09f89d269f175%7C0%7C1%7C637243544976816719&sdata=b3XDqJ7qKh0%2BEVfGW9lvm%2Fj05gX4jB2GG7R25SzGf2g%3D&reserved=0>, > University of Oxford > Creator, Rapid-Reviews.info > <https://eur02.safelinks.protection.outlook.com/?url=http%3A%2F%2Frapid-reviews.info%2F&data=02%7C01%7C%7C118846187a3f4c43279208d7f1a0bcaa%7Cd47b090e3f5a4ca084d09f89d269f175%7C0%7C1%7C637243544976816719&sdata=%2BNkFiaVs6MT30E9noZiPCO0FLSPAFz5g4UdaBkAnJ2s%3D&reserved=0> > > > ------------------------------ > > To unsubscribe from the EVIDENCE-BASED-HEALTH list, click the following > link: > > https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=EVIDENCE-BASED-HEALTH&A=1 > <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.jiscmail.ac.uk%2Fcgi-bin%2Fwebadmin%3FSUBED1%3DEVIDENCE-BASED-HEALTH%26A%3D1&data=02%7C01%7C%7C118846187a3f4c43279208d7f1a0bcaa%7Cd47b090e3f5a4ca084d09f89d269f175%7C0%7C1%7C637243544976826715&sdata=1IA0JzifHCgGnRnI%2FL9HU%2BgC%2BumCbSOA9zuROihaXXo%3D&reserved=0> > > > > > ---------------------------------------------------------------------------------------------------------------------- > > Pantycelyn yn agor mis Medi 2020. > https://www.aber.ac.uk/cy/accommodation/accommodation-options/catered/pantycelyn/ > > Pantycelyn opening September 2020. > https://www.aber.ac.uk/en/accommodation/accommodation-options/catered/pantycelyn/ > > > ---------------------------------------------------------------------------------------------------------------------- > > Prifysgol Aberystwyth www.aber.ac.uk/cy/ > > Prifysgol y Flwyddyn yng Nghymru - 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