The quotes in the table below are taken from the APHA county epidemiology reports recently released. Progress is clearly not on target. As seen in Oxfordshire (see here), bTB in the Edge Area is not being addressed with sufficient resources or the right approaches. The lack of adequate testing is so glaringly obvious it is beyond belief that this situation is being allowed to continue. The bovine TB eradication policy is in tatters not just in the HRA and LRA but in the Edge Area too.
County
Progress
Going Well?
Berkshire
“Looking at the recent trend, the likelihood of achieving a herd prevalence of less than 1% OTF-W incidents in Berkshire by 2025 is low.”
No
Buckinghamshire
No prediction
?
Cheshire
“..the prevalence (4.4%) in 2023increased marginally compared to 2022. OTF county status will not be achieved by 2025,but with the use of all available tools to identify and to reduce the burden of infection, it might be possible to achieve OTF status by 2038.”
No
Derbyshire
“Based on current information, achieving OTF status is not conceivable for Derbyshire by 2025. Residual infection continues to be a problem in Derbyshire. The reasons for this are unclear, may be multi-factorial, and is likely to include herd type, wildlife populations, farming practices and proximity to the HRA county of Staffordshire.”
No
East Sussex
“The increase of prevalence rate from 2022 in addition to the geographical extension of the endemic area (HRA prior to 1 January 2018) suggests that East Sussex will not be able to achieve OTF status by 2025. The prevalence and incidence will need to have a considerable reduction through the next 10 years to ensure that OTF status in the county could be reached by 2038.”
No
Hampshire
“The likelihood of achieving a herd prevalence of less than 1% OTF-W incidents in the county by 2025 is low.”
No
Leicestershire
“Although the herd incidence declined again in 2023, it is unlikely that Leicestershire will achieve OTF status by 2025.”
No
Northamptonshire
“Despite the declining herd incidence and prevalence trends over the last 3 years in Northamptonshire, it seems unlikely that the county will be eligible for OTF status by 2038.”
No
Nottinghamshire
“Additionally, prevalence in Nottinghamshire at the end of the reporting year was 1.7%. It seems unlikely for Nottinghamshire to become eligible for OTF status by 2025, as set out in the strategy for achieving OTF status for England, published in 2014. However, if the disease trend continues to decline as a result of effective disease control measures it is possible Nottinghamshire will achieve OTF status by 2038.”
No
Warwickshire
“Official-TB-Free status (OTF) for Warwickshire will not be achieved by 2025, as set out in the ‘Strategy for Achieving OTF Status for England’, published in 2014. However, progress is being made and the outlook is positive.”
No
Recurrence
‘Recurrence’ is where bovine TB returns to a herd after a period when it has not been detected by periodic testing. Recurrence is the result of residual infection, ineffective testing and cattle movements, (with the odd unevidenced nod to wildlife). Recurrence is now recorded consistently across the Edge Area and the High Risk Area, and it is the reason why the Edge Area is unlikely to be TB free by 2038. APHA diverted gamma testing in 2021 to herds with a history of recurrence and persistence, at the same time reducing parallel testing of gamma alongside the skin test in OFT-W (Officially TB Free Withdrawn) herds, resulting in early undetected disease remaining in herds throughout the Edge Area.
It’s interesting to note that ‘Overall Recurrence’, ie recurrence during the herd’s lifetime, has been added to the recently published epidemiology reports (see below). Previously, recurrence has only related to the previous 3 years. ‘Overall Recurrence’ reflects the true seriousness of the epidemic.
And alongside the reality of the problem of Recurrence, the APHA are still blaming badgers for significant disease transmission without evidence, and still claiming disease benefit from badger culling without evidence.
Bovine TB failings in Oxfordshire and beyond in 2023
The “Year End Descriptive Epidemiology Reports” for Bovine TB control were published by APHA online on 24th October for the Edge Area counties of: Berkshire, Buckinghamshire, Cheshire, Derbyshire, East Sussex, Hampshire, Leicestershire, Northamptonshire, Nottinghamshire, Oxfordshire and Warwickshire.
The report for Oxfordshire is the most extensive of the county reports (see here). What does it tell us about the progress made on bTB control as measured by cattle herds withdrawn (so-called ‘confirmed’ breakdowns) in Oxfordshire? And what does it tell us about APHA’s approach to epidemiological standards? It looks like they are still blaming wildlife by default………….
Ups and Downs
In Oxfordshire, following a continual decrease in OTF-W (Officially TB Free Withdrawn) breakdown incidents since 2018, the number of incidents rose from 31 in 2022 to 41 in 2023, which is similar to the numbers of incidents in 2020 (47 OTF-W). The number of OTF-S (Officially TB Free Suspended) incidents also rose slightly from 25 in 2022 to 28 in 2023. This is the highest number of OTF-S incidents in the last 10 years.
The APHA say that having originated in West Oxfordshire, East Oxfordshire is now the main driver of bTB spread in the county, especially during the last three years, with an increase of OTF-W incidents in 2023. This suggests that TB is actively spreading in East Oxfordshire, despite the initial decrease in the total number of incidents and following use of interferon gamma (IFN-γ) blood testing and increased SICCT testing in 2018.
Unscientific inference
Despite APHA’s consistent inability to scientifically attribute bTB disease benefit to badger culling, they casually state that persistent incidents have decreased due to“implementing control measures such as badger culling since 2019”.
In 2023, additional Defra approved ancillary tests (IFN-Y & IDEXX) for use in Oxfordshire to “remove infection in incidents where the level of reinfection from purchases and wildlife was believed to be low, but where the effect of residual infection was preventing incidents from becoming clear”. It is not clear what exactly leads APHA to believe infection in wildlife is low in this instance, when they consistently say that it is high elsewhere. Perhaps due to removal by shooting of around 2,500 badgers in Oxfordshire’s Cull Area 49 (West Oxfordshire) in an area overlapping with Gloucestershire?
Deer are next in the blame game
Reports of suspicion of TB in wild deer increased in 2023. This is likely due to the creation in 2022 of the Oxfordshire Cluster Project, which offered training to local deer stalkers to identify typical lesions of TB in game carcasses.
Not surprisingly with greater checks, wild deer carcasses with TB lesions were reported to APHA in 2023: two roe deer, one fallow and one muntjac. All were sampled and sent for TB culture and bTB clade B6-62 was confirmed in all of them which is the common clade in Oxfordshire cattle. Whole Genome Sequencing (WGS) was employed by APHA to link “incidents to specific cattle incidents in the same geographical area”, with a claim of ”further evidence of the relationship between cattle and local wildlife in the transmission of TB”, without evidence of the relationship and direction of infection. Inconclusive epidemiology.
The Bird-flu distraction claim
The APHA also claim that an increase in recorded bTB incidence in cattle in 2023 followed an emergency interim action in December 2021, diverting APHA staff to addressing the 2021-2023 highly pathogenic avian influenza (HPAI) outbreaks. Gamma testing was prioritized to the LRA and Edge Area counties on 12-month testing (not 6-monthly) during that time, further reducing the number of tests in Oxfordshire. APHA view this change in gamma policy as likely to have contributed to slowing the decrease in incidence in 2022 and for the increase in 2023, amongst other factors. However, in addition, the reduction of EU finance after Brexit was a driver to reducing disease eradication effort.
APHA in a muddle?
APHA say that licensed intensive badger culling operations started in the west side of Oxfordshire in 2019, while the first large area in Oxfordshire was Cull Area 49 commencing 2020. In 2021 a Cull Area 61 further north was commenced with an additional Cull Area 69 on the East side of the county starting 2022.
Guess-estimated Cull Area boundaries in Oxfordshire with year of start
APHA claim that badger culling has “probably started to have a positive impact in western areas of the county but not yet in the… east of the county where TB is spreading further east.” This is simply more unevidenced guesswork and is completely unacceptable, probably driven by one or two individuals who have over-invested in badger blame and who stands to lose a lot from being wrong about the whole sad process and because they have mislead hundreds of others.
Clusters
APHA claim that “clusters” of bTB breakdowns provide evidence of local spread, and say that where local cattle purchase has not occurred, cattle herd incidents are most likely caused by wildlife. Once again they are speculating – pointing by default to badgers where there is no obvious purchase of cattle to blame; undetected disease in the herd and very many other possibilities are once again ignored.
Clusters were first identified in Oxfordshire in 2017. WGS investigations and ‘phylogenetic trees’ have increased knowledge of the transmission of M. bovis, but APHA say that they ”cannot always” answer the direction of transmission and/or ancestry due to limited numbers of isolates. But in truth this is not possible in any of their investigations – they need to stop pretending and misleading readers of their reports. And the farmers should not put up with these misdescriptions – it is costing them dearly to be given inaccurate advice.
We know that badgers have been tested for bTB in cluster areas but how this work is being done is hidden in secrecy.
Unevidenced ‘risk pathways’ again
APHA list the following main ‘risk pathway’s and key drivers for TB infection within Oxfordshire in 2023 in the following order:
exposure to infected local wildlife
movement of undetected infected cattle
residual infection from previous incidents.
Astonishingly, the APHA still put infected wildlife at the top of their list of risk factors for TB incidents in cattle in 2023. Could this be because they are still using the discredited Disease Report Form (DRF), which blames badgers by default, when there is no clear infection route from cattle? There was an impression in 2023 that the DRF was being phased out but APHA seem trapped in a neglectful poorly functioning system where blaming badgers fills the gap of attribution being uncertain due to inadequate investigation and testing.
These incidents are far more likely to be from undetected disease in cattle. Once again without evidence, APHA still pedal the same old rhetoric that they have still been telling vets and farmers: “most common source of transmission from wildlife identified during on-farm investigations were potentially infected badgers, but the presence of other wildlife species such as wild deer is increasingly reported in some areas”. Adding as some kind of ‘get out of jail if wrong’ statement that there is “high uncertainty as to their [bagders] role in transmitting TB to cattle”. It’s an utter disaster area. They also admit that distinguishing source attribution between badgers and residual cattle infection in recurrent incidents is difficult, but claim it is likely “a combination” of both factors. Muddling cattle movements with unevidenced badger infection somehow suits their old arguments but muddles vet and farmer understanding. Basically, the APHA are still pointing to badgers as an important source of infection, misleading the industry without any evidence. .
Tricking the vets and farmers – residual infection is the key
As now appreciated by the BBC 2 documentary on the work of the Save Me Trust and Dick Sibley in Devon and elsewhere – looking at the APHA reporting of 3 yearly recurrence data and recurrence in the lifetime herd history, you can see that 82% of incidents reported across Oxfordshire were in herds with a history of TB during the herd’s lifetime, including more than 3 years previously. Recurrence of bTB is due to undetected residual infection coupled with cattle movements. It is the result of insensitive tests. This is where the problem lies and with current approaches APHA have no chance of disease control – it is one huge failure.
Whilst APHA do accept residual cattle infection as an important problem and note the tendency of incidents in Oxfordshire to be more chronic and recurrent, they still cling on to badger blame. Why they do so is extraordinary, but relates to a shrinking group of individuals so wedded to it being the case; as a group they dare not change position. The only thing that will make that happen is if farmers and vets stand up to how they are being grossly mislead by those who effectively control them.
Introduction of systematic supplementary Gamma testing since 2018 has increased the overall sensitivity of testing in herds and reduced the likelihood of infection being left in the herd at the end of a TB incident. Good progress was being made but (as above) this supplementary testing has been reduced in the last two years and targeted to a limited number of herds with recurrent and persistent incidents. Absolute madness – why are the livestock farmers not jumping up and down about this slackening off?
Sadly, the picture is the same across other counties. In Cheshire, for example, 86% of incidents reported across the region were in herds with a history of TB in the herds lifetime, including in the three previous years. It’s really not rocket science.
A messy complicated picture
The number of herd incidents of TB per year in Oxfordshire remained high over the last 5 years, with a decreasing trend in 2021 and 2022, before reverting in 2023 to the same levels as seen in 2020. The epidemiological picture has become more complex in recent years with multiple clusters, some of which have only recently become apparent. APHA say that this “does not favour the long-term objective of reducing OTF-W incidence to less than 1% in Oxfordshire by 2038.”
The future look bleak
British farming is staring down the barrel of an even greater bTB disaster. APHA and their badger blame game story are in danger of making a new High Risk Area out of the Edge Area and risk infecting the entire country.
APHA are at least emphasizing the importance of the early detection of infection through more frequent surveillance testing of cattle herds, alongside the use of mandatory gamma testing on all OTF-W incidents. And now alongside other Defra approved ancillary testing by informed case management, recognising lack of sensitivity of current tests (SICCT) as a potential issue. But not with sufficient emphasis and determination to mend the current broken system. Disciplined pre and post movement testing are still approached in an ineffective way, despite their pivotal role in stopping transmission. This has been clearly known and ignored since 2018 when the issue was pointed out to the Godfray Review..
APHA’s continued blaming of badgers for a significant proportion of cattle bTB infections is now a real barrier to disease control that risks pulling the beef and dairy industries further into disaster. The scientific evidence APHA skews to blame badgers is ridiculous and as the 2038 ambition dissolves, the stakes are being raised higher and higher. Who will be the first to realise and take urgent action to prevent the worsening of this national disaster? Those in charge might answer.
The figures speaks for themselves. Herd BTB breakdowns in the very first cull area in Gloucestershire have changed little since 2013, after nine years of persistent badger culling.
With a downward trend in ‘confirmed’ (OTFW) breakdowns prior to the start of culling, data is consistent with benefits from continued enhanced cattle controls hitting the limits of their effectiveness. But the poor sensitivity of the skin test has retained diseased cattle less responsive to the SICCT and gamma test, and kept the area as diseased as it was at the start. Elsewhere in Gloucestershire it’s a similar story. A humiliating moment for Defra and APHA, who know that badger culling is ineffective and that the BTB testing procedures need a revolution, much as they do in Republic of Ireland. There is a dire need to drill down on the disease, especially in the larger dairy herds. Without this £Millions of taxpayer and farmers money will be wasted each week chasing impossible outcomes.
Area 1-Gloucestershire has seen a large percentage rise in number of cattle (up by 20% or 4,124), despite the number of herds decreasing by 13. It is well known that disease rises as herds get larger, so why are the public being asked to support a process that is making things worse? And who is going to step up to resolve the crisis?
The continuing questions over uncertainty in the published outcome of the Randomised Badger Culling Trial (RBCT) have rumbled on over the summer of 2024, and were reported on (here).
Why are the statistical elements of the RBCT so important? Because the government badger cull policy rests all but entirely on them. It was the science that DEFRA has used to create policy and in court to defend their decisions to experiment with badger culling. The RBCT claimed badger culling can reduce bovine TB in cattle; very many subsequent studies are heavily derived from it, to the point that if it is wrong, it will send a wrecking ball through dozens of publications, reports and reviews. The stakes could not be higher.
Disease benefits claimed for badger culling by civil servants and politicians are in reality, far more likely due to implementation of additional cattle measures. But there is continued inference that badger culling is a cause of disease reduction because such benefits might be “predicted” from the results of the RBCT.
The chronology of published and pre-printed science on the statistical analysis of the RBCT as it relates to proactive culling is growing, so here is a summary with clickable links:
The ‘Comment’ submission to the Royal Society Open Science is an extensive response to the two new Mills et al. (2024) papers which reproduced much of Torgerson et al.’s models, whilst re-interpreting the results.
The abstract of the Torgerson et al. ‘Comment’ is as follows:
Abstract Re-evaluation of statistical analysis of the Randomised Badger Culling Trial (RBCT) by Torgerson et al. 2024 was rebutted by Mills et al. 2024 Parts I and II. The rebuttal defended the use of count rather than rate when considering bovine tuberculosis herd incidence. The defence makes biologically implausible use of Information Criterion for appraisal diagnostics; overfits data; and has erroneous Bayesian analyses. It favours ‘goodness of fit’ over ‘predictive power’, for a small data set, when the study was to inform application. Importantly, for ‘total’ bTB breakdown: (‘confirmed’ (OTF-W) +‘unconfirmed’ (OTF-S)), where modern interpretation of the main diagnostic bTB test better indicates the incidence rate of herd breakdown, there is no effect in cull and neighbouring areas, across all statistical models. The RBCT was a small, single experiment with unknown factors. With respect to the paradigm of reproducibility and the FAIR principles, the original RBCT analysis and recent efforts to support it are wholly unconvincing. The 2006 conclusion of the RBCT that “badger culling is unlikely to contribute positively to the control of cattle TB in Britain” is supported, but the route to such a position is revised in the light of modern veterinary understanding and statistical reappraisal.
The new Comment, that has not yet been peer-reviewed, highlights what is described as selective reporting, misleading interpretation, implausible model selection and coding anomalies. It will be of interest to Ministers, Civil Servants, scientists and politicians who currently, under the new Labour administration, are ‘refreshing’ the bovine TB strategy, and policy.
The two Mills et al. papers were published just a few days before the Intensive and Supplementary badger cull licences were issued for 2024, providing a rationale for culling to continue.
The ‘targeted’ badger culling proposals of the last Government are rejected by the new Labour Government but the ‘ineffective’ badger culls still continue, pending a further Review.
Lawyers acting for Secretary of State for Secretary of State for Environment, Food and Rural Affairs (DEFRA) Steve Reed, have responded to ecologist Tom Langton’s Judicial Review Application [AC-2024-LON-002292] against a ‘future of badger culling’ Consultation (here) prepared by the previous administration. Specifically, the March 14th Consultation had proposed a new wave of ‘targeted‘ badger culling across England, killing many thousands of badgers each year, potentially until 2038.
The controversial proposals were promoted by the Chief Veterinary Officer Christine Middlemiss’s disputed beliefs that badgers play a central role in the spread of cattle TB, the science of which Langton, with other veterinary experts has challenged in recent years (here).
Defra have confirmed their decision not to proceed with proposals to introduce and license targeted culling across England. Defra had received multiple objections to the Consultation as well as support for proposals to better identify cattle disease risks that will still go forwards. The response indicates that the Secretary of State will instigate a fresh review of future bovine TB policy.
The welcome news signals a shift from previous policy but is bitter-sweet, with the news that a new badger cull area is being planned: Cumbria’s Eden valley South of Carlisle and to the east of Penrith under a Low Risk Area (LRA) policy licence. Communications have been sent to Tony Juniper at Natural England objecting to the consideration of any new LRA licence, on scientific grounds, but so far there has been no substantive response, with a failure to curtail culling licences that are ongoing from before the general election. It is expected that Natural England will reauthorize licences for over 20 intensive culling areas agreed under previous policy arrangements that many think should also be cancelled. These are in addition to those completing supplementary culls, meaning up to 20,000 badgers will be shot at night over the next twelve weeks with a percentage dying slowly from shot wounds in ways found cruel by a government appointed expert group in 2014.
Concerns remain that despite withdrawing the cull consultation proposals, the Defra’s response leaves some important question unanswered. This includes speculation in a heavily disputed recent Animal and Plant Health Agency report. Further, the Defra response to the economic aspects of culling states that the costs of badger culling may not outweigh the economic benefits, a point of interest in the Government spending rounds in the coming months.
Tom Langton said:
“This is a small but important step towards bringing forwards the abolition of badger culling forever. Labour has previously stated that culling is ineffective and now the Government has scrapped a Consultation that claimed culling worked. But it is shameful that the Labour administration is continuing the badger culls and expanding them in the Low Risk Area, contradicting its manifesto pledge, to appease a vocal minority based upon old scientific rhetoric and dogma.
Bovine tuberculosis is a disease of mammals needing expert measures that have been neglected for reasons demonstrated in the recent BBC documentary LINK charting the work of Brian May and the Save Me Trust with farms in England and Wales.
Badger culling must stop, but most of all a new testing regime for cattle is needed to give farmers the powers to use the right tests at the right time to beat TB in the herd where a hidden reservoir remains. Something that red tape presently prevents and at massive unnecessary cost to the taxpayer. It could be resolved in an afternoon with the right people around the table. I urge Defra to listen to us as they have promised and to meet with my team to help formulate new policy.”
Langton added;
Meanwhile, I would also very much like to thanks my legal team: Lisa Foster and Hannah Norman at Richard Buxton and Richard Turney and Ben Fullbrook at Landmark Chambers and with Dominic Woodfield from Bioscan as expert witness on the ecological impacts issues. And last but not least all of the Badger Trusts, Groups, Charities and generous individuals around Europe who have combined to form the Badger Crowd. With the specific aim of creating a voice for and to bring justice to the fight for truth surrounding badger culling. With a key role played in recent months by Protect the Wild, promoting awareness and fundraising.”
Further information
Defra’s decision was made on 23rd August, the date the BBC documentary of Brian May’s research was first screened (watch here), showing the inadequacies of the current cattle testing system.
The Defra response does not address the ecological impacts issues correctly and does not even seem to understand the challenge relating to protected species away from designated nature areas. Dominic Woodfield comments:
“Defra’s acknowledgement that the scientific, ethical and economic justifications for the extirpation of tens of thousands of badgers annually since 2013 have collapsed, is welcome but long overdue. It is tragic that it has needed the pressure of repeat litigation by Tom and others, the publication of competing science exposing the fallacy of blaming and slaughtering wildlife for a disease rooted in poor livestock management practices and failures of animal husbandry, and a change of the party in Government for them to finally concede the point.
Even now, Defra continue to disregard the wider ecosystem level effects of removing an apex predator from wide swathes of England – we may never now know what impacts this has had (and continues to have) on our native wildlife and declining species. Tom’s and others’ persistence in the face of obduracy, reliance on poor science and the making of decisions based on the political clout of those lobbying for the status quo, is extraordinary and commendable, but it is also fuelled by the long-held conviction that they were fundamentally right. There are a very small and diminishing number of hiding places left for those who’ve pinned their reputations and careers on badger culling as being a rational or effective answer to the bovine TB problem.
In life generally people crave the truth, learn from the truth and act on the truth. Truth is the universal source for learning, where trust develops, and where solutions to tackle the myriad of challenges that life throws at us are fostered.
Yet, we all know that absolute truth is a fickle thing. As time passes, new insights evolve, things change. Gradually we may find that what we thought we knew is conditional on certain things, right only some of the time, or even wrong for a clever reason.
So care is needed, especially with the big decisions where large amounts of money, time and effort are employed to address a particular issue or problem.
Take for example the culling of badgers. A Government expert [1] concluded 20 odd years ago that a very small trial study [2] suggested badgers might spread bTB to cattle, especially if frightened away from the setts where they live, and shooting them would help.
Sounds ridiculous? The entire livestock industry eradication policy in GB and Ireland has been based around ‘badger blame’ for the spread of Bovine tuberculosis among cattle herds for two decades. There has been over £2 Billion of subsequent spending and hundreds of thousands of badgers have been culled around a truth that is now uncomfortable to lose, because so many people have enthusiastically believed and embraced it. They own it, and accepting it is wrong messes badly with what they have said and done over the last 20 years.
The matter came into sharp focus in March of 2024, just weeks before the general election was called, with a Government Agency staff academic paper on badger culling effort [3] in England since 2013. This, followed shortly by a DEFRA Public Consultation [4] aimed at extending badger culling for a decade or more, over further huge areas, but with even fewer constraints on when, where and how.
To the general public this is all a mystery. Surveys show that the public largely think that badger culling ended in 2020 when Government said it was ‘phasing it out’, and the new government’s election manifesto view [5] that it has been ‘ineffective’ means it will stop for good. But actually, in the cold night air, from Cornwall to Cumbria, guns with silencers are steadily slaughtering tens of thousands of badgers each autumn. As harvest 2024 is concluding, the culling is now ramping up yet again.
So what about the truth? Well Steve Barclay MP, the old Defra Minister, one of the few seniors to keep his seat during the Labour landslide, had claimed in an ebullient foreword to the March consultation, that a 56% benefit has been gained after four years of culling badgers down to under 30% of their numbers.
So let’s unpack the truth in that. Firstly, the key time marker in all this is 2016 when the first of ten large cull areas were all up and running and followed by around 60 more at a starting rate of around ten a year. Unfortunately for unpicking science and truth, this was also the time that more intensive cattle testing began ramping up. So telling between the effect of culling and testing is not possible, despite what Barclay claimed.
‘Ah’, say the boffins at the Government Agency for badger culling. ‘But without killing badgers, the cattle tests wouldn’t work so well.’
At this point most people switch off….’ I dunno…suppose it’s possible…I’m not that interested actually….’ It’s one of those speculation moments that is only so interesting given that the facts and alternatives are beyond the non-specialist’s reach and require weeks of fact-checking. This is indeed a complex issue, even for interested parties to consider.
So where did Barclay’s view come from? Well, back in 2012 the coalition government encouraged an academic paper in 2013 [6] that was timed to support badger culling, and that printed its truth, as a part of the justification for mass badger culling. The paper said a few things that we now know were right and wrong thanks to good old Captain Hindsight.
Right, was that the old small study had been rendered meaningless by a horrendous Foot and Mouth disease outbreak in 2001 [7] that mucked up the experiment’s need for ‘stable countryside’ to be able to monitor change in three of the ten areas – enough to spoil the results. The hapless NFU encouraged rapid restocking with untested TB infected cattle, firing up the bTB epidemic.
Wrong were the calculations that rested upon a belief that cattle do not give bTB to badgers. It was thought to be TB moving all one-way, from badger to cattle, that Defra believed in those days, something that was always suspicious and that modern studies now show is wrong [8-11].
And questionable too was a theory, to try to make the numbers add up in a way no one has ever explained and that looks implausible. That theoretical infections going from badger to cattle are somehow passed on more rapidly than those originating from cattle. Baffling?
Lost already? Well to make the old small study work, the boffins believed that while around 94% of disease was the result of cattle-cattle infection, around 6% was down to badgers. Unfortunately, wildlife groups have believed and utilized these figures, despite warnings, not realising it is part of a dubious study that blames badgers and the king pin in justifying the badger culls since 2013. The so called ‘onward transfer’ of infection from badger to cattle is akin to a biblical myth with no scientific legs, yet it became the truth that key people in Government believed. It was held up as the science to believe in, forming and promoting the badger cull policy. Most cull objectors had realised this by 2016.
Back to Barclay’s 56% and the boffins new paper in March 2024. Despite elaborate graphics, this was a pretty rough-and-ready analysis, looking at before and after culling and substantial cattle testing improvements in the first few years of application, and attributing the decline in herd TB breakdowns to a combination of badger culling and herd testing. It stated (twice) that it is not possible to say which factor caused the change. Yet in a discussion of the results it also said the results were consistent with effects of badger culling seen during the small study, and studies using the small studies assumptions, and this speculation found itself in the paper summary (abstract) at the front. This now gives an opportunity for apparent disease benefit to masquerade as fact or truth. Hence Barclay and the National Farmers Union ramped up the rhetoric on ‘Badger Culling Works’, and quoted the 56% benefit as a function of badger culling. Not bTB control – the better description of the mix of things being tried. Without evidence. Sunak picked up the mantle and did the same in a shed with farmers shortly before he lost office at the general election.
But the truth, as pointed out by other senior academics observing, is that these public statements were untruthful. Change might or might not have been assisted by badger culling – the very question the small RBCT study 20 odd years ago was supposed to resolve when it came up with a split answer – it possibly does and it possibly doesn’t. Flip a coin. And the real truth is that badger culling could be having some effect or it might all be down to tougher testing and movement control. Saying badger culling helped from 2013 or was pivotal or a catalyst is a bit like any of the innumerable causation arguments that created problems in science before they were recognized for what they were during the 1960’s [12]. Association is not the same as causation. Would anyone propose that Donald Trump being elected as President in 2016 caused bovine TB to start to fall? Well it happened at the same time, and bTB has come down since………..Or was the fall in TB the result of a general switch to tougher testing?
The problem for truth in this case is that Governments need to make decisions, and where there is uncertainty they need to have a plan. But Government scientists presenting their opinions as fact, for politicians and stakeholders to believe and to repeat, is a deception. A dangerous step and something that needs weeding out by journals employing peer-reviewers. And hopefully not by mournful inquiries years later, charged with working out how it all went wrong. The problem here is that there are few people experienced enough to understand and judge boffin science, and so you find your mate reviewing your work, and you review your mates work, and bad habits develop. Bovine TB science is plentiful and this syndrome sees awkward material published quite often; it provides a good exemplar of the issue called the reproducibility crisis [13]. All the Government scientists need to say is we ‘think’ it might be working because…. that is a long way from saying it ‘is’ – think snake oil salesman. It matters, it matters a lot when lots of lives and money are at stake. It matters because lying to the public is undemocratic and wrong.
So if someone asks you about badger culling, you might just say – ‘well its complicated and I don’t know.‘ But if they pick up a gun to shoot a badger, you might just say ‘hang on – I think you might be breaking the law’. Which requires evidence, and sufficient clarity that mass killing badgers to prevent the spread of bovine TB can be justified. And after 20 years there is no truth to suggest it does, only guesswork. However, cattle testing and movement control has worked in England and Wales without badger culling, so using that proven remedy is justified with some confidence and is an honest approach, if truth be told.
References
1. King, D. 2007 Bovine tuberculosis in cattle and badgers. A report by the Chief Scientific Advisor, Sir David King, to the Secretary of State for Defra on 30 July 2007.
2. Donnelly, C. A. et al. Positive and negative effects of widespread badger culling on tuberculosis in cattle. Nature 439, 843–846 (2006).
3. Birch, C. P. D. et al. Difference in differences analysis evaluates the effects of the badger control policy on bovine tuberculosis in England. Sci Rep 14, 4849. https://doi.org/10.1038/s41598-024-54062-4 (2024).
4. DEFRA 2024 Bovine TB: Consultation on proposals to evolve badger control policy and introduce additional cattle measures. A consultation exercise contributing to the delivery of the government’s strategy for achieving bovine tuberculosis free status in England..
6. Donnelly, C. A. & Nouvellet, P. The contribution of badgers to confirmed tuberculosis in cattle in high-incidence areas in England. PLoS Curr. 10, 5 (2013).
7. Private Eye 2001 Special Report. Not The Foot And Mouth Report. London
8. Biek R, O’Hare A, Wright D, Mallon T, McCormick C, Orton RJ, McDowell S, Trewby H, Skuce RA, Kao RR. Whole genome sequencing reveals local transmission patterns of Mycobacterium bovis in sympatric cattle and badger populations. PLoS Pathog. 2012;8(11):e1003008. doi: 10.1371/journal.ppat.1003008. Epub 2012 Nov 29. PMID: 23209404; PMCID: PMC3510252.
9. Crispell J, Benton CH, Balaz D, De Maio N, Ahkmetova A, Allen A, et al. Combining genomics and epidemiology to analyse bi-directional transmission of Mycobacterium bovis in a multi-host system. Elife. 2019;8
10. Akhmetova, A; Guerrero, J; McAdam, P; Salvador, LC; Crispell, J; Lavery, J; Presho, E; Kao, RR; Biek, R; Menzies, F et al. 2021. Genomic epidemiology of Mycobacterium bovis infection in sympatric badger and cattle populations in Northern Ireland. bioRxiv 2021.03.12.435101; doi: https://doi. org/10.1101/2021.03.12.435101
11. van Tonder AJ, Thornton MJ, Conlan AJK, Jolley KA, Goolding L, Mitchell AP, Dale J, Palkopoulou E, Hogarth PJ, Hewinson RG, Wood JLN, Parkhill J. Inferring Mycobacterium bovis transmission between cattle and badgers using isolates from the Randomised Badger Culling Trial. PLoS Pathog. 2021 Nov 29;17(11):e1010075. doi: 10.1371/journal.ppat.1010075. PMID: 34843579; PMCID: PMC8659364.
12. Hill, Austin Bradford. “The Environment and Disease: Association or Causation?.” Proceedings of the Royal Society of Medicine 58 (1965): 295.
13. Baker, Monya, 2016, “1,500 Scientists Lift the Lid on Reproducibility”, Nature, 533(7604): 452–454. doi:10.1038/533452a
Brian May: The Badgers, the Farmers, and Me’ is a documentary that was aired on BBC2 at 9.00pm on Friday 23 August, and is now available on the BBC iplayer. Filmed over 4 years, the programme charts Brian May’s journey as he explores the ongoing battle against bovine tuberculosis, and the differing views of both farmers and those who oppose badger culling .
The new film covers 12 years of practical research ongoing over the last 12 years. The shocking truth around the monumental failure of Defra to effectively address the problem of bovine TB is highlighted, and the resulting tragic slaughter of both cows and badgers is revealed with horrible clarity.
Animal campaigner Brian May and Anne Brummer, CEO of May’s Save-Me organization, have spent the years since culling was first mooted by David Cameron’s government uncovering the truth about bovine TB. Rather than fighting the farmers, May and Brummer have looked at the problem from the viewpoint of the farmer and the vet , following a case study which has transformed a chronically infected cattle herd into a healthy herd with TB-free status. This was achieved without killing a single badger. The revolutionary methods used are now known as the Gatcombe strategy.
Meanwhile, over the same period, nearly a quarter of a million badgers have been killed on the basis that they spread bTB to cattle. This new documentary shows that the badger cull policy implemented since 2013 has failed farmers completely. Rates of bTB infection and consequent numbers of cattle slaughtered are in some areas no better, and in others worse than ever, following the cull. The work from the case study farm in the documentary clearly shows with that blaming badgers has been a wildly incorrect reading of the facts.
May and Brummer conclude that the very idea that badgers are part of the bTB re-infection process is unsupportable. Government and NFU policy has been based on the work of a small number of scientists who have persisted in claiming disease benefit from statistical models, ignoring the uncertainty around them, and doubling-down when challenged.
This new documentary is the first time that an alternative view about badger culling has been presented in documentary format. Do watch it for a sincere, refreshing and honest take on badger culling. It goes to the heart of the problem, and shows compassion for the farmers, the cattle and badgers. And it provides answers and a way forward. Congratulations to all involved.
On December 13th 2022, a preprint was put up on the ResearchSquare platform. Entitled ‘Absence of effects of widespread badger culling on tuberculosis in cattle’[1], it was a reanalysis of the Randomized Badger Culling Trials (RBCT). Following a protracted period of review, with a number of very long silences, and relatively few revisions, it was published in Nature Scientific Reports on July 15th 2024 (Torgerson et al 2024) [2]. Finding a major anomaly, it uses a range of statistical models to re-examine the RBCT data and concludes that most standard analytical options did not show any evidence to support an effect of badger culling on bovine TB in cattle.
Torgerson et al 2024 [2] noted that the statistical model selected for use in the original study in 2006 [5] was one of the few models that did show an effect from badger culling. However, various model assessment criteria suggest that the original model was not an optimal model compared to other options available. You can read a short blog on the new Torgerson et al paper here, and the full paper is available here. Essentially, the more appropriate models in the latest study strongly suggest that badger culling does not bring about the disease reduction reported.
Following publication, the new analysis [2] was mentioned in an article in Vet Times on July 24th, and in Vet Record in their 3/10 August edition. Neither publication noted its major significance. No other mainstream media reported on it at all. This is perhaps surprising since the government badger cull policy rests all but entirely on the conclusions from the RBCT. It is the science that DEFRA has used in court to defend their decisions to experiment with culling. It is the science that has resulted in 11 (12 including 2024) years of intensive and supplementary badger culling across huge areas of England, and around 230,000 dead badgers. In other words it is the pivotal piece of work for the decision-making around badger culling policy.
The reluctance of the media to report further on Torgerson et al. is a prelude to work by two of the authors of the original 2006 analysis (Christl Donnelly and Rosie Woodroffe) together with a DPhil Statistics student at Oxford University (Cathal Mills), who had, at the time of publication, two rebuttal papers in press with Royal Society Open Science [3,4]. Unusually, the abstracts and supplementary information for these new papers were posted online and available to view before publication without the main text. Enquiries regarding the posted information and the main papers resulted in in press versions being helpfully forwarded. The new analyses from Mills et al. are entitled An extensive re-evaluation of evidenceand analyses of the Randomised Badger Culling Trial (RBCT) I: Within proactive culling areas [3], and An extensive re-evaluation of evidence and analyses of the Randomised Badger Culling Trial II: In neighbouring areas [4].
Published on August 21st, the two new papers largely duplicate the analyses in Torgerson et al 2024, but use different model assessment criterion to come to a different conclusion. In fact they double-down on the conclusions of the original 2006 analysis: “…we estimate substantial beneficial effects of proactive culling within culling areas, consistent with separate, existing, peer-reviewed analyses of the RBCT data.”
So in the year and a half since the posting of the Torgerson pre-print [1], Mills, Woodroffe and Donnelly have been working on their rebuttal to it. Torgerson and his team have looked through the in press versions of the Mills et al (2024) publications [3,4] for a few days and multiple problems stand out. In particular:
Incorrect statements regarding disease control outcomes since 2010
Use of a non-peer reviewed publication
Confusion between the offset and overdispersion leading to incorrect calculation of disease exposure
Incorrect and confused statements regarding model comparisons
Exaggerated claims during use of new modelling.
Failure to address the modern interpretation of SICCT test reactors
Failure to recognise the onward effect of the analytical failure on multiple subsequent publications and policy outcomes.
Somewhat unusually, the new Mills et al papers do not refer to or cite the published Torgerson et al paper [2], only the first pre-printed version of Torgerson et al. from 2022 [1]. So in essence, the new Mills et al papers [3,4] are out of date at the time of publication, failing to refer to the updated 2023 preprint or the final version in Scientific Reports published 15th July 2024 [2]. Following contact with the Royal Society, a response raising concerns with the newly published papers is being written and will be submitted shortly. An interim report has been put together by Torgerson and Langton with brief observations on the new papers (see here).
The Royal Society says it is committed to reproducibility. Reproducibility is the ability of independent investigators to draw the same conclusions from an experiment by following the documentation shared by the original investigators [6]. The issues identified in [2] and “rebutted” in [3,4] illustrate one of the major issues of the reproducibility crisis: poor statistical inference. It is hoped that the conclusions of this exchange will inform future bovine TB intervention policy this autumn.
Things are starting to become slightly clearer as we near the point of discovery over the future of badger culling in England and beyond. Consultees to the online Defra Consultation questionnaire of 14th March were told this Monday (5th August) that an analysis of Consultation responses will be published in the autumn (Sept-Nov?) giving more time for policy development without badger culling. But there is no reason now to delay clarification on the big 56% lie surrounding the ineffective badger culls.
Notably, the NFU appeared fully taken in by the spin from the Animal and Plant Health Agency paper by Colin Birch and Defra, that badger culling ‘is working’. Birch et al. follows on from a paper published in Veterinary Record in 2022 that showed quite neatly how recorded bovine TB levels (recorded OTF-W incidence) peaked after the introduction of annual tuberculin testing in 2010 and began dropping in the High Risk Area from 2013 in some counties and generally by 2015. And, at a steady rate that did not increase once badger culling started (and that was more widespread from 2018), showing no evidence that badger culling had contributed to a slow decline of around 6% per year.
Steve Barclay, and previous Environment Ministers before him, had made wild claims of a culling benefit of around 50%, based on APHA parroting the claims made since the 1970s that this is the badger contribution to cattle TB. This has always been a poorly evidenced, lame and far-fetched claim, making a mockery of professional epidemiology.
Not to be fooled, Labour are onto the problem and have firmly labelled badger culling as ‘ineffective’ in their manifesto. They have highlighted the need to work with farmers and scientists which is now the helpful – but not very specific – new Defra mantra.
The Birch paper makes it quite clear in two places that the cause of the welcome decline in bTB first identified formally in 2022, cannot be attributed to any particular intervention, be it better testing, different tests and more frequent tests, better biosecurity or badger culling. It is just a crude before-and-after effort with no controls, showing what was already known in a slightly clunky way. This is no help at all, as Professor Macdonald at Oxford pointed out in his November 2023 ‘state of the science’ review. However, the unfortunately misleading abstract for the Birch paper transmutes opinion into ‘fact’, to give the casual reader a misinformed overview of the findings. How very CVO.
So what are we left with as we approach the time of Labour’s big reveal this month? Firstly, an increased interest in badger vaccination with Defra organising a media spree with its dutiful contractors to suggest a direction of travel that Natural England seem to think is appropriate.
Peter Brotherton, Director of Science at Natural England, issued his “Advice to Natural England’s Operations Team on Supplementary Badger Culling 2024” in April 2024, see here. It was released under Freedom of Information at the end of May.
So how is supplementary culling being justified?
Brotherton considers that the ‘key insights’ arising from his appraisal are that “disease reduction benefits to cattle achieved through badger culling are sustained in the long term (likely at least 7 years post-cull).” And what is this based on? Brotherton says:
“The most relevant evidence to the current English situation is from Donnelly (2013) who found from the Randomised Badger Control Trial (RBCT) that the disease reduction benefits from four years of intensive culling of badgers are greatest 1-2 years post-cull and are sustained for at least 7 years, albeit at a diminishing level over this period.”
Professor Paul Torgerson, Chair, Veterinary Epidemiology, University of Zurich
The problem for this justification now, is that Donnelly (2013) (an unpublished report) is overturned by the new peer-reviewed paper by Torgerson et al (2024). Published since Brotherton issued his advice, “Absence of effects of widespread badger culling on tuberculosis in cattle” has shown that the original RBCT analysis (Donnelly et al 2006) used an inappropriate calculation of rate, when face value calculation of rates was available. When rates are calculated in the standard way, no effect of culling was found. Many subsequent studies, like Donnelly & Nouvellet (2013) which recycle the approach of that analysis should now be considered unsafe. There are dozens, possibly hundreds of them.
Brotherton also references two small studies, Byrne et al 2014 (4 areas in Ireland) and Clifton-Hadley 1995 (2 areas in south-west England) which he acknowledges may be less relevant to the current English context. They are too small in scale to be able more than anecdotal or provide any certainty. They certainly should not be used as substantive evidence.
And that seems to be pretty much it in terms of published evidence. There is some speculation without evidence. There is a mention of badger vaccination reducing the prevalence of bTB in badgers, but any assumption of this reducing disease in cattle is not based on sound evidence. It should be noted that Natural England keep away from their ‘Uncertainty Standard’ that they previously reported as scrapped, but now seem to want to retain .. its all a bit uncertain at Natural England.
Notably, Brotherton does not refer to the main peer-reviewed and published badger culling analysis Langton et al (2022) in his ‘rationale’, presumably favouring the Chief Vets unqualified comments. This compared culled and unculled areas after 7 years of industry-led badger culling (2013-2019) and found no measurable benefit.
Also of note is Brotherton’s recollection of the advice of the previous Chief Scientific Advisor Prof. Boyd, who “stressed the limits in the evidence base and the importance of adjusting the policy as new evidence becomes available.“ There is no sign that the evidence of peer-reviewed Langton et al (2022) and Torgerson et al (2024) is being recognized by NE yet.
Badger Crowd understands that Natural England have received a letter requesting that supplementary badger cull licences should be revoked on the basis of new published science. It’s well past time to stop the badger cull immediately on the scientific evidence, and not least the comprehensive peer-reviewed evidence.
On Thursday 18th July, as Keir Starmer visited Blenheim Palace in Oxfordshire, the Oxfordshire Badger Group (OBG) presented a petition, with over 50,000 signatures to Oxford University School of Biology in central Oxford.
OBG called on Oxford University to own what it called “YOUR FLAWED SCIENCE” and asked them to “SPEAK OUT AGAINST BADGER EXTERMINATION.”
OBG press statements say that Oxford University is the birthplace of the Badger Culls. Scientists from Oxford, with others, designed, conducted and analysed data from the original Randomised Badger Culling Trial (1998-2005). It is the findings from this trial that DEFRA has used to claim that badgers have a substantial role in spreading bovine TB (bTB), and to justify killing badgers on an industrial scale. Since 2013, over 230,000 badgers have been slaughtered, most of them completely healthy adults and cubs. Cull zones now cover much of the west and central England. Badger populations are reported to be close to local extinction in some areas. Over 60% of Oxfordshire is covered by various cull areas, along with neighbouring counties, infected in more recent years by careless cattle movements.
Oxfordshire Badger Group say it has been pleading with Oxford scientists over the past year to use their influence in the badger cull debate. But the School of Biological Sciences has declined to engage in meaningful way, snubbing any chance of a serious dialogue.
OBG representatives said:
“We ask them to speak out against the misuse of their research. Keeping silent on one of the major animal welfare issues of the day is not scientifically principled. It allows DEFRA and Natural England to ignore new evidence and keep on culling regardless. Their silence is deadly for badgers, does not help farmers or cattle and is condemned by many members of the public. Our petition and open letter “Oxford University’s Scientists Must Speak Out Against Badger Extermination” now has over 50,000 signatures.”
The university scientists have said in correspondence that they have ‘no appetite’ to revisit the RBCT in the light of new evidence. They refuse to engage in what they see as a political rather than a scientific debate, which it is not – it is a scientific debate. Yet this is a pivotal moment. DEFRA are considering moving to ‘targeted culling’ with no credible evidence other that its’ pilot cull in Cumbria has failed.
The new Labour government manifesto states that badger culling is ‘ineffective’, yet is still allowing it to continue, even as government-funded scientific evidence against culling piles up. DEFRA’s own scientists analysed the overall impact of implementing a range of bTB control measures (cattle measures and badger culling combined). They did not find clear evidence to link culling badgers to a reduction in bovine TB (see section on Birch et al here). Yet the paper by Birch was widely and incorrectly reported as showing that culling badgers had reduced the incidence of bTB by 56%.
In April 2024, Natural England’s Director of Science advised against issuing supplementary cull (SBC) licences stating “Over the past few years, the balance of evidence has shifted….” and “….. farmers can avoid the considerable expense and inconvenience of undertaking the SBC without increasing the risk of their cattle suffering from bTB”. Officials overruled this advice and badgers are now being killed over the summer (including we believe Oxfordshire Cull Zone 49 which already had completed 4 years of intensive culling).
Professor David MacDonald reviewed the evidence base for the current cull policy for the Badger Trust in November 2023. He concluded “in 2023, much as in 2007, it is hard to see that killing badgers will make a meaningful contribution”. Sadly, his fellow scientists have chosen not to support this narrative.
The RBCT was a politically charged, high profile research project that ran for 8 years and cost UK taxpayers ~£49 million. Perhaps the worst transgression in science is when you don’t admit that you are fallable. If you do admit oversights or mistakes, you are a good scientist. Badger Crowd supports OBG in calling for Oxford Scientists to pursue scientific rigour in acknowledging the new understanding of the science that has developed over the last few years and that changes the narrative. We ask that they join us in calling for an immediate end to the badger cull as they did in 2012 before it started and in 2015 before it was rolled out. Why not now, at the time when they predicted it would fail?
Eileen Anderson OBG Trustee said:
“It is horrible knowing that innocent badgers are being killed across Oxfordshire, in contradiction to the science and with so little concern for their lives or the survival of a native mammal.”
Linda Ward OBG Trustee said:
“The scientists were reluctant to openly challenge the former Conservative governments pro-cull policy. But to continue to keep silent in the face of the emerging new evidence would be inexcusable and call their scientific integrity into question. In my view they need to either publicly defend their RBCT or accept that it’s findings are flawed.”
Julia Hammett Chair of Trustees said:
“Oxford University’s research has enabled the cattle industry to kill 230,000 badgers. DEFRA is openly ignoring the scientific evidence that culling is not associated with a measurable reduction in bTB. The eminent scientists who led the RBCT must demand that the government returns to robust, evidence based policies.”
Please speak up Oxford University. It’s well past time to stop the cruel, wasteful useless badger cull.
This website has been reporting on the legal challenges to the badger culling policy and licences, and the science that has supposedly supported it since 2019. Over that time, there have been many jaw-dropping moments; government interference in peer-reviewed science, government scientists getting their data wrong in published letters, Natural England claiming that culling has no effect on ecosystems and then desperately covering their tracks in the courts. The list goes on, and the story that has unfolded remains truly shocking.
Professor Paul Torgerson, Chair, Veterinary Epidemiology, University of Zurich
But an even more dramatic sequel to this long-running saga is the new scientific paper published this week in Scientific Reports by Professor Paul Torgerson and colleagues including Badger Crowd’s Tom Langton. We will be posting a video presentation that will put this new work into context and demonstrate the massive impact that it should now have on Government bovine TB policy.
Why is this new study so important?
Because the government badger cull policy rests all but entirely on the conclusions from the Randomised Badger Culling Trial (RBCT). It is the science that DEFRA has used in court to defend their decisions to experiment with culling. The study is the original peer-reviewed science that claims badger culling can reduce bTB in cattle; many subsequent studies are derivative from it, use the same flawed methodology, or suffer heavily from confirmation bias. I.e. they are subjective opinion that fails to prove that culling badgers causes disease reduction. However, benefits are claimed from culling when any benefits are, in reality likely from cattle measures. This is because such benefits are “predicted” from the results of the RBCT.
What does the new study say?
The new study re-examines data from the RBCT experiment using a range of statistical models. It concludes that most standard analytical options did not show any evidence to support an effect of badger culling on bovine TB in cattle. The statistical model selected for use in the original study in 2006 was one of the few models that did show an effect from badger culling. However, various criteria suggest that the original model was not an optimal model compared to other analytical options then available. The most likely explanation for the difference in result from the different analyses is that the RBCT proactive cull analysis ‘overfitted’ the data and used a non-standard method to control for disease exposure. The result is that the original model had a poor predictive value, i.e. it was not useful in predicting the results of badger culling. The more appropriate models in the latest study strongly suggest that badger culling does not bring about the disease reduction reported.
How might the RBCT scientists defend their decisions?
The RBCT was a pre-planned analysis i.e. data was analysed in the way they said it would be before they started the trial, so it can’t be questioned. This is not the case. There was a loosely described plan to compare rates of disease between culled and unculled areas. Their published analysis in fact compared counts of disease between culled and unculled areas. Would the conclusion of the RBCT analysis have been different if incidence rates had been analysed correctly? Yes it would. Even if the data had been analysed according to any ‘pre-plan’, this would not preclude subsequent re-analysis using correct and more appropriate methods, except you might not do it if you believed rates had been used as was suggested in the paper.
There is nothing wrong with using the model to calculate the number of herds (exposure). There may be circumstances in which a model may be sensibly used to calculate exposure. However, the original model used suggests that bTB herd incidents (a standard measure of new disease) is independent of the number of herds in a study area. That is, if the number of herds in an area is doubled, the incidence does not change. This is not credible. Not least because the RBCT report (Table 5.4) showed that breakdowns doubled in cull and control areas over the period of study.
You are just model dredging; i.e. you are just picking out the model that says what you want. The new study re-examined RBCT data using a range of statistical models (22 in total). Most of these show no evidence to support an effect of badger culling on bTB in cattle. The statistical model chosen by the RBCT study was one of the few models that did show an effect, but when tested in an accredited way, it is not an optimal model. The new paper is not guilty of “model dredging”, it is the result of an attempt to find a robust analytical method that could support the claims of the RBCT
Why has this not been picked up before?
It does seem remarkable that the original RBCT a) got through peer review, and b) has not been challenged since. One reason might be the rather casual use of the words ‘rate’ and ‘count’ in the original paper, which implies that rate has been used in the model, whereas in fact an epidemiologically non-standard method was used to calculate a rate. Supplementary information in the original paper showed standard calculated ‘rates’ and the assumption could have been made that these were what was used in the model. They were not.
Interestingly, in the journal Biostatistics in 2010, two authors of the 2006 paper discussed approaches to using a range of statistical methods on a data set to compare their performance, and the choosing of a planned statistical approach that best complimented the subject matter. They proposed that selection of a specific statistical approach may involve ’subtle considerations about the interplay between subject-matter and statistical aspects and the detailed nature of the data and its compilation.’ And with respect to the peer-review of results, they contend quite boldly: ‘the suggestion of requiring independent replication of specific statistical analyses as a general check before publication seems not merely unnecessary but a misuse of relatively scarce expertise.’
This may go some way towards understanding how problems with the original analysis were not picked up for such a long time. And it goes some way to explaining why there is such a reproducibility crisis in science.
The ‘Comment’ submission to the Royal Society Open Science is an extensive response to the two new Mills et al. (2024) papers which reproduced much of Torgerson et al.’s models, whilst re-interpreting the results.
