Category Archives: Director’s Choice – From the Journals

It is Really True: Detailed Analysis Shows that Social Media Really do Lead to Silo Thinking

It is popular to claim that social media sites (SMSs), such as Twitter and Facebook, democratise knowledge. This is true in one sense – it places information within the easy reach of the population at large. Individuals certainly benefit.[1] But what about society at large? Here the story is bleak. Far from bringing people into contact with ideas that might challenge their precepts, SMSs increase intellectual isolation. Walter Quattrociocchi, writing in Scientific American,[2] summarises the mountain of data that has been painstakingly collated by himself and others; they analysed data from two million Facebook users in one study.[3] People eschew views they find challenging and isolate their attention in online groups, which reinforces their pre-existing beliefs. It gets worse – the less educated a person, the more isolationist they tend to be. Such people hew to conspiracy theories, which grow like a snowball among online communities. Scientific analysis is shut out so that detailed analysis of data on topics such as climate change are less widely disseminated. Conspiracy theories proliferate, for example, saying that climate change is a hoax perpetuated to further academic careers and earnings of alternative energy suppliers. The very worst news is that campaigns aimed at debunking these myths actually reinforce belief in conspiracy theories; there is no antidote to the myths perpetuated down social media.

SMSs are here to stay, but as the author says, the Information Revolution is fostering an Age of Credulity not an Age of Enlightenment.

— Richard Lilford, CLAHRC WM Director


  1. Lilford RJ. The Second Machine Age. NIHR CLAHRC West Midlands. 5 May 2017.
  2. Quattrociocchi W. Why Social Media Became the Perfect Incubator for Hoaxes and Misinformation. Scientific American. April 2017.
  3. Del Vicario M, Bessi A, Zollo F, et al. The Spreading of Misinformation Online. Proc Natl Acad Sci USA. 2016; 113(3): 554-9.

Providing Care at Less Cost – the Great Skill-mix Debate

Health care professionals do not all receive the same emoluments. In all countries doctors are paid the most. They carry the greatest responsibility for making decisions that affect people and they are the most likely to be sued – so their differential pay seems fair. But the other side of the coin is that non-doctor health professionals can do many things equally well, or perhaps better. Similarly, there are things that Community Health Workers can do as well or better than nurses, and again at lower unit cost. There are many types of skill mix initiative, and the most widely used classification emanated from Bonnie Sibbald,[1] herself a previous CLAHRC director:

Sibbald’s Skill-Mix Classification

Changing roles

  • Extending roles
  • Substituting – exchanging one type of worker for another
  • Delegation
  • Innovation – creating new jobs

Changing structures at the interface between services

  • Transferring service from one setting to another
  • Relocation
  • Liaison

There are a number of systematic reviews on skill-mix summarising a great many articles. However, review authors agree that there is little clear evidence on effectiveness or cost-effectiveness. Many studies concentrate on skill substitution, usually comparing doctors and nurses.[2] However, the subject is hard to study, and deriving generalisable conclusions is always going to be difficult because of differences in context – especially training. One cadre that has received a lot of attention over the last two decades involves innovation more than substitution – the use of Community Health Workers. They have a valuable role in prevention (e.g. malnutrition/vaccination), maintenance of therapy (e.g. HIV, TB and hypertension), and frontline care (e.g. rehydration therapy), as discussed in previous News Blogs.[3-5]

— Richard Lilford, CLAHRC WM Director


  1. Sibbald B, Shen J, McBride A. Changing the skill-mix of the health care workforce. J Health Serv Res Policy. 2004; 9(s1):28-38.
  2. Antunes V & Moreira JP. Skill mix in healthcare: An international update for the management debate. Int J Healthc Man. 2013; 6(1): 12-7.
  3. Lilford RJ. Lay Community Health Workers. NIHR CLAHRC West Midlands News Blog. 10 April 2015.
  4. Lilford RJ. An Intervention so Big You Can See it from Space. NIHR CLAHRC West Midlands News Blog. 4 December 2015.
  5. Lilford RJ. Between Policy and Practice – the Importance of Health Service Research in Low- and Middle-Income Countries. NIHR CLAHRC West Midlands News Blog. 27 January 2017.

Government vs. Private Schools

CLAHRC WM is not just interested in health care since the methods we use are equally relevant to decision-makers in education, social services, industrial policy, criminology, and so on. We should all be learning from each other. In a previous blog I reported on the (mostly positive) results of the ‘Moving to Opportunity’ experiment in the USA, where families were given an opportunity to move from a deprived neighbourhood to a more salubrious one. So I was interested to spot an RCTs of vouchers that allowed children (over a wide age range) from government schools to attend private schools (also in the USA).[1] The experiment was recent (last five years) and we have outcomes at one year only. Seventy percent of pupils allocated a voucher to attend a private school took up their offer; so both intention to treat and per protocol analyses are reported. The educational outcomes were lower in the intervention group, and were statistically significantly lower for mathematics. This negative effect was greater if the voucher was taken up than if it was not. The negative effect was greater if the child came from a school that was not rated as poor performing than if the previous school was rated satisfactory or good. The negative effect was greatest if the child was in elementary school, and non-significantly positive if they were already in high school.

What caused the negative effect on educational outcomes? Simply moving school does not seem to explain the results, since a proportion of control children moved school with little or no apparent effect. However, private schools provide less instructional time than government schools, especially in elementary school. Other studies have also noted negative effects of moving children to private school on educational outcomes in the short term. But it is far too early to declare the intervention a failure. There is a limit to how much an elementary school child can assimilate, and it is the long-term effects that are important. However, I was surprised by this result – educational interventions have a habit of producing results different to those intended. Full marks to the US Congress, which had the wisdom to evaluate its own policies. The UK Cabinet Office has published a document arguing for more RCTs of policy,[2] and I expect to be able to report the results of further RCTs of educational interventions in the News Blog.

— Richard Lilford, CLAHRC WM Director


  1. Dynarski M, Rui N, Webber A, Gutmann B, Bachman M. Evaluation of the DC Opportunity Scholarship Program. Impacts After One Year. Alexandria, VA: Institute of Education Sciences, 2017.
  2. Haynes L, Service O, Goldacre B, Torgerson D. Test, Learn, Adapt: Developing Public Policy with Randomised Controlled Trials. London: UK Cabinet Office, 2012.

Bariatric Surgery – Improve Five-Year Outcomes

The short-term (2-3 year) outcomes of bariatric surgery have been extensively studied in RCTs, and the (mainly) positive outcomes documented. Now we can use unbiased information to look a little further into the future as longer-term outcomes of an RCT of bariatric surgery have been published.[1] Outcomes were assessed at the age of five years among 150 overweight, type 2 diabetic people randomised to intensive medical therapy alone versus such therapy accompanied by bariatric surgery (by-pass or gastric size reduction). At five years the differences in HbA1c were massive – 2.1 points vs. 0.3 points improvement over baseline. The surgical group were thinner, had improved blood fats and reported better quality of life.

So what are the service implications of this iconic study? We need to ‘industrialise’ surgery, so that more operations can be done at a given cost. That means teams of technicians operating under consultant (anaesthetist and surgeon) supervision. Here is an artist’s representation of such a ‘Taylorised’ process:

An Operations Director oversees a Surgeon and two Anaesthetists who oversee six technicians operating on six patients

Such a process was established to improve access to cataract surgery in Moscow over three decades ago.[2] Similar processes have been used with respect to open heart surgery in the US. I propose we should conduct simulations and then move gradually and incrementally to a safe, but efficient, method of implementing high-throughput bariatric surgery. Evaluation of the roll-out would be essential. Barriers will need to be overcome, but one or two effective demonstration sites will speak more than volumes of words. My only real concern is that some new ‘technology’ will come along and sweep away bariatric surgery and all its (protesting) practitioners.

— Richard Lilford, CLAHRC WM Director


  1. Schaeur PR, Bhatt DL, Kirwan JP, et al. Bariatric Surgery versus Intensive Medical Therapy for Diabetes – 5-Year Outcomes. New Engl J Med. 2017; 376: 641-51.
  2. Schmemann S. Moscow Eye Doctor Hails Assembly-Line Surgery at Clinic. The New York Times. 2 July 1985.

Wait Until Your Symptoms are Really Bad Before Having an Osteoarthritic Joint Replaced

Early studies of hip replacement showed that the operation was associated with large and sustained QALY gains, and hence that it was cost-effective. The same applied to knee replacement. The patients in these studies all had severe disease, as shown by their quality of life scores at baseline. But indications for both operations have gradually expanded so that the majority of current patients who receive the operation are atypical of those in the original studies. That is to say, their disease is less severe. The long-term benefits of hip replacement have been found to be modest in recent studies, doubtless because patients with less severe disease have less capacity to benefit.[1] Now a large American study [2] has reported similar findings with respect to knee replacement, confirming that the operation is only cost-effective in people with severe pain and  limitation of movement at baseline. As in many medical/surgical treatments it is important to stratify by baseline severity. Absolute (and sometimes relative) benefits fall as baseline severity decreases, thereby radically shifting the harm to benefit ratio.

— Richard Lilford, CLAHRC WM Director


  1. Beswick AD, Wylde V, Gooberman-Hill R, Blom A, Dieppe P. What proportion of patients report long-term pain after total hip or knee replacement for osteoarthritis? A systematic review of prospective studies in unselected patients. BMJ Open. 2012; 2: e000435.
  2. Ferket BS, Feldman Z, Zhou J, et al. Impact of total knee replacement practice: cost effectiveness analysis of data from the Osteoarthritis Initiative. BMJ. 2017; 356: j1131.

Theory of Mind in Tennis

On Tuesday nights I play tennis with my friends; Zac, Boris and Sergei (not their real names). CLAHRC interventions are often heavily based on behaviour change, and so I have had to brush up on my psychology. But is this knowledge of any use in tennis? In the following few editions of the News Blog I shall explore the modern psychological theory in the context of my feeble attempts at tennis. I shall start with the idea of a “theory of mind”, most often related to Tomasello.[1] [2]

Zac hates it when I intercept his powerful return of serve. So I know that when my partner, Sergei, next serves to the seething Zac, he will be predisposed to punish my impecuniousness by hammering his return down my tram line. To reduce this risk I should position myself towards the edge of the net. But Zac knows that I know that he is seething, and therefore that I will anticipate the tramline shot. He will anticipate my preventive action, which would open up the centre of the court, enabling him to pass me and place the ball on my partner’s backhand. So, I must anticipate his anticipation… This is an archetypal example of a theory of mind – the ability of humans to anticipate the effects of their actions in the mind of other humans. If Zac and I could undergo functional MRI on the court, then the complementary parts of our brains would brighten up in a kind of dance. So, I position myself if an intermediate position – I do not cower over the tramline, nor do I move aggressively to mid-court. Zac has three options – risk the tramline shot, go for mid-court, or play a standard cross-court shot. If he has read my reading of his reading of my mind, he will go cross-court. But what if he has anticipated I have anticipated that he has anticipated!

Tennis court showing three possible shots - tramline shot, shot to backhand, or 'default' cross-court shot

— Richard Lilford, CLAHRC WM Director


  1. Carpenter M, Nagell K, Tomasello M. Social cognition, joint attention, and communicative competence from 9 to 15 months of age. Monogr Soc Res Child Dev. 1998; 63(4): 1–143.
  2. Tomasello M, Carpenter M, Call J, Behne T, Moll H. Understanding and sharing intentions: The origins of human social cognition. Behav Brain Sci. 2005; 28: 675–735.

Another Excellent Paper on Economic and Mortality Inequality from Currie & Schwandt

In the latest News Blog [1] (before the election purdah) I covered Case and Deaton’s monumental study of death rates among white people in the US.[2] I briefly mentioned the idea that childhood (and even pre-natal) exposure can ‘programme’ the body, leading to mortality differences in later life. This can lead to exaggerated estimates of the effects of economic conditions and behaviours in later life on health and life expectancy. There is strong evidence that patterns of behaviour in adulthood are laid down by the age of three.[3] Failure to give due consideration to prior conditions can also lead to poor interpretation of life expectancy statistics. Life expectancy (say at birth) is derived, perforce, from the current age-specific mortality rates at all (subsequent) ages.[4] So there is an assumption that when a baby born in 2017 reaches age 40, she or he will be subject to the current mortality rates for 40 year olds, and so on. That is a massive assumption, given the above point concerning early childhood effects on adult health.

The subject of wealth and health is replete with academic bear traps. Mortality is rising among poor white people,[5] as we pointed out in a previous News Blog.[6] But then the composition of poor white people changes over time. So the mortality of poor white 40 year old women cannot automatically be ascribed to any recent change in the behaviours or exposures of such women. It could be attributable to their early life exposures. Likewise, Hispanic children have been dropping out of school in the US at progressively lower rates. So any observation comparing the health of drop-outs over time is highly biased – the same types of people are not being compared. And when it comes to ethnicity, things get harder still because the way ethnic groups are classified is ephemeral.

Currie and Schwandt use counties in the US as the basis for comparative statistics.[7] They use three year averages to reduce noise, and they measure the socio-economic standards of counties in different ways – poverty rates, high-school completion rates, and median income. They look at age-specific death rates, life expectancy (as a consolidated measure of death rates over all ages), and age/sex adjusted differences by race.

What do they find in their study covering the years 1990-2010?

  1. Life expectancy is increasing across the US, but us doing so to a greater extent in poorer areas than in richer ones.
  2. This relative improvement in poor counties compared to rich counties is seen particularly among women.
  3. And in children under the age of five (see a previous News Blog [6]).
  4. Inequalities in death rates in young adults are also declining.
  5. But over age 50, inequalities in mortality increased for women while remaining unchanged in men.
  6. For black children, inequalities narrowed compared to white children.
  7. The increased health inequality of white adults cited in our last News Blog is confirmed (phew!).

There are other interesting findings. I would have thought that immigrants would have worse outcomes than age and race matched residents, but the opposite is the case – at least for Hispanic people. A massive study of identical twins separated at birth would be needed to sort out cause and effect relationships (and even that would not be perfect). However, taken in the round, the news from the USA is good regarding inequalities; poor white people aside. Let me therefore end with a quote from the article – you can make of it what you will:

It sometimes seems as if the research literature on mortality is compelled in some way to emphasize a negative message, either about a group that is doing less well or about some aspect of inequality that is rising.

— Richard Lilford, CLAHRC WM Director


  1. Lilford RJ. Ever Increasing Life Expectancies Come to an Abrupt End Among American Whites. NIHR CLAHRC West Midlands News Blog. 5 May 2017.
  2. Case A, & Deaton A. Mortality and morbidity in the 21st century. Brookings Papers on Economic Activity. BPEA Conference Drafts. March 23-24, 2017.
  3. Suzuki E, & Fantom N. What does “life expectancy at birth” really mean? The DATA Blog. 11 November 2013.
  4. Lilford RJ. More on Brain Health in Young Children and Effect on Life Course. NIHR CLAHRC West Midlands News Blog. 24 February 2017.
  5. Chetty R, Stepner M, Abraham S, et al. The Association Between Income and Life Expectancy in the United States, 2001-2014. JAMA. 2016; 315(6):1750-66.
  6. Lilford RJ. Relative Wealth and Health. NIHR CLAHRC West Midlands News Blog. 6 May 2016.
  7. Currie J & Schwandt H. Mortality Inequality: The Good News from a County-Level Approach. J Econ Perspect. 2016; 30(2): 29-52.

Brain Activity and Heart Disease – a New Mechanism

The amygdala is a key component in the ‘salience network’ of the brain. This network is activated in conditions of fear and stress. A recent elegant paper in Lancet [1] examined the relationship, first, between amygdala activation (measured by PET scanning) and cardiovascular outcomes, and second, between activation of the amygdala and certain mediators of cardiovascular disease concerned with stimulation of bone marrow to produce inflammatory cells and with arterial inflammation. They showed positive correlations in all cases. I am interested in causal modelling,[2] [3] and I was therefore provoked by the authors’ ‘mediation model’, which I take to be a form of structural equation modelling. This suggested that only half of the amygdala’s ‘effect’ on cardiovascular disease could be explained by the two mechanisms proposed above (production of inflammatory cells and arterial inflammation). This paper represents a potential step change in understanding brain-body interactions, but I await replication with interest.

— Richard Lilford, CLAHRC WM Director


  1. Tawakol A, Ishai A, Takx RAP, et al. Relation between resting amygdalar activity and cardiovascular events: a longitudinal and cohort study. Lancet. 2017; 389: 834-45.
  2. Lilford RJ, Girling AJ, Sheikh, et al. Protocol for evaluation of the cost-effectiveness of ePrescribing systems and candidate prototype for other related health information technologies. BMC Health Serv Res. 2014; 14: 314.
  3. Watson SI & Lilford RJ. Essay 1: Integrating multiple sources of evidence: a Bayesian perspective. In: Challenges, solutions and future directions in the evaluation of service innovations in health care and public health. Southampton (UK): NIHR Journals Library, 2016.

Yet More Evidence that Patient Safety Culture Measures, Measure Nothing

Searching for a patient safety culture measurement ‘tool’ is like a search for the Holy Grail. I think that it is a search for something that does not exist. If safety culture exists, then safety practices should correlate within organisations. They don’t.[1] [2] Meddings, et al. [3] seem slightly surprised by their finding that bloodstream infections improved in many US hospitals with absolutely no change in safety culture. Of course, if you teach ‘safety culture’ to staff then their scores will improve as they have learned the correct answers. But there is little evidence that, absent such a change, improvements in safety are related to a measurable construct of culture.

— Richard Lilford, CLAHRC WM Director


  1. Wilson B, Thornton JG, Hewison J, Lilford RJ, Watt I, Braunholtz D, Robinson M. The Leeds University Maternity Audit Project. Int J Qual Health Care. 2002; 14(3): 175-81.
  2. Jha A, & Pronovost P. Toward a Safer Health Care System. The Critical Need to Improve Measurement. JAMA. 2016; 315(17): 1831-2.
  3. Meddings J, Reichert H, Green MT, et al. Evaluation of the association between Hospital Survey on Patient Safety Culture (HSOPS) measures and catheter-associated infections: results of two national collaboratives. BMJ Qual Saf. 2017; 26: 226-35.

Nodding Syndrome: Autoimmune Reaction to the Parasitic Worms That Cause River Blindness?

We have described the above enigmatic disorder of young children in East Africa before; a degenerative brain disease characterised by repetitive nodding movement, an inability to swallow, and eventually global brain failure.[1] Authors of a recent study hypothesised that the disease may be caused by an autoimmune response to the river blindness parasite.[2] They detected auto-antibodies to the parasite more often in cases than age-matched controls from the same village. The antibody attacks various cell markers in the mouse brain among neural networks that are affected in nodding syndrome. But only about half the patients with nodding syndrome exhibited the antibodies. The authors speculate that a number of yet to be identified antibodies may also be involved. I wonder why the disease does not map onto the geography of river blindness, which appears to be much broader than that of nodding syndrome.

So, here is my hypothesis. Remember, a few News Blogs ago,[3] I articulated a ‘three hits hypothesis’ as the cause of many diseases. One example was cytomegalovirus infection, which in the presence of the malaria parasite, and along with genetic predisposition, leads to Burkitt’s lymphoma. So I suspect that exposure to river blindness may be a sensitising event, and propose a search for a further exposure that is more specific to the ‘nodding syndrome belt’ extending from South Sudan, through Uganda to North Tanzania (see Figure).

Map of African countries showing where River Blindness is endemic and where outbreaks of Nodding Disease have occurred.

Data on River Blindness taken from the World Health Organization.

— Richard Lilford, CLAHRC WM Director


  1. Chilton PJ. A Mysterious Disease with Unknown Cause. NIHR CLAHRC West Midlands News Blog. 27 June 2014.
  2. Johnson TP, Tyagi R, Lee PR, et al. Nodding syndrome may be an autoimmune reaction to the parasitic worm Onchocerca volvulus. Sci Transl Med. 2017; 9.
  3. Lilford RJ. Three Hits Hypothesis. NIHR CLAHRC West Midlands News Blog. 7 April 2017.