Select Committee on Environment, Food and Rural Affairs Minutes of Evidence


Examination of Witnesses (Questions 380 - 399)

WEDNESDAY 24 OCTOBER 2007

SIR DAVID KING AND PROFESSOR MARK WOOLHOUSE

  Q380  Patrick Hall: But the area of disagreement is in terms of the interpretation of the data. You are not undermining the scientific data or the methodology but the conclusions. That is what matters. It is the conclusions and therefore what is done that matters. I would have thought it would have been consistent with your role that you would challenge and question and discuss the conclusions that have come from the interpretation of the data. You have not done that. You have not done that perhaps because there was not a lot of time. I wanted to establish whether you had done that or not, and you have not.

  Professor Woolhouse: Professor Bourne was strongly suggesting that there was an attempt to undermine the statistical analysis of other data, and that is emphatically not the case. You are quite right; it is the interpretation, particularly the interpretation going beyond the actual study that they were reporting on that was being discussed. It is what we do next. This report has been submitted; it tells us a lot. The conclusions are equivocal. In fact, the Godfray Committee said in 2004 that they were going to be. You were warned in 2004 that we were going to get equivocal results from this trial. What then do we move on to? What does the scientific evidence point to next?

  Q381  David Taylor: You say you are not challenging the scientific approach of the ISG, but in paragraph 37 of your report, in the second sentence, when talking about whether or not the disruption of badgers was a permanent effect, you say: "However, there is a reasonable possibility that the disruption is transient." You are taking out altogether the ISG's conclusion that it has a permanent effect. Secondly, in paragraph 41 you comment on the ISG's statement that "badger culling cannot meaningfully contribute to the control of cattle TB in Britain". You just say: "However, the data do not support such an unqualified conclusion." You are criticising their conclusions without really giving the scientific background to that. Thirdly and finally, at one point you talk about hard geographical boundaries without adducing any scientific evidence whatsoever, for instance that arable land of at least one kilometre wide—your suggestion—is any barrier to badger movement or indeed that rivers, motorways and so on act in the ways that they do and suggest they do. You are criticising them for things which you then go on and repeat yourself.

  Professor Woolhouse: The rivers, motorways and coastlines point is actually raised in the ISG report. There are far fewer inconsistencies than you are implying between the science and—

  Q382  Chairman: You say that but you do not, if you like, qualify the difference. You talk about the same kinds of hard boundaries which the ISG did but then say that if they do not exist, perhaps some soft boundaries in the operative kilometre-wide land in certain areas will probably do so, but there is no quantification scientifically, mathematically or in any way as to the difference between the effects of these different types of boundaries. It is almost saying that any boundary will do that as long as it is above 100 square kilometres area-wise.

  Sir David King: Can I just try to explain that, Chairman? The existence of a boundary we would all agree will reduce the impact of the perturbation. That is the important point we are making, not that it will eliminate it but that it will reduce it and anything that is done to reduce the perturbation is going to reduce the negative impact of the cull. Whether that boundary is a river, an ocean or a motorway, it is going to reduce it. I do not think either, Chairman, that anyone would argue that a large strip of arable land would be a good way to avoid these effects because the effects arise from the in movement of badgers from outside the cull area. If we have no cattle outside the cull area, then of course there is no effect.

  Q383  Chairman: In paragraph 28, and I do not want to labour the point, you again deal with this perturbation effect almost by saying that the numbers of perturbed badgers will go down if you increase the frequency of culling within your defined areas. You almost seem to be saying that. Maybe I have misunderstood it.

  Professor Woolhouse: I do not think that is right. That is to do with the possible transient nature and negative effect. Going back to your previous point, another difference of interpretation between the Irish trial and the RBCT is that the Irish trial was actually chosen with natural barriers in mind. That has been published as the reason why there are those different results. The idea that barriers would help ameliorate any negative effect I think is quite well supported.

  Q384  Chairman: One of the things that is increasingly difficult for all of us to take on board is that when we look at Professor Mollison's critique of what you have said, he for example talked in general terms about what you did by saying that it was unbalanced and inexpert. He goes on to comment: "Next, his report is mainly concerned with detailed discussion of complex statistical modelling and data analysis issues. Yet neither he nor any of his `expert' group have expertise in this area comparable with Professors Cox and Donnelly of the ISG." Finally, there is quite a long paragraph in which he questions your epidemiological analysis. He describes it as "muddled in its discussion of the basic concept of R0 and on a substantive point, the result of Cox et al indicated an R0 of... ." He is giving you a really good panning in terms of your methodology and approach. He was the independent statistical auditor for the Randomised Badger Culling Trial for seven years, from 2000 to 2007. If you were inviting peer review, you appear to have got it.

  Sir David King: This is not peer review, Chairman. This is mud slinging. What you have just quoted are attacks on personalities. I am very happy to have details of what we have said approached in a peer-review style. Look at the list of people who assisted me: Tim Roper, ecologist and a badger expert; Douglas Young, immunologist, a microbiologist from Imperial College; Mark Woolhouse, one of the country's leading epidemiologists; Dan Collins, veterinary medicine and animal clinical studies in Dublin, and again his expertise is specifically in the area of animal TB; and Paul Wood from Australia, the person who developed one of the critical tests for cattle TB and who is internationally seen to be one of the experts. To call that a group that is not expert in the area is simply totally mistaken. I am going to ask the expert on my right to make some specific comments on that.

  Professor Woolhouse: You mentioned two things. You mentioned the alleged criticism of the statistical approach taken by the ISG to which Denis Mollison refers. Yes, I think there are some quibbles about some of the clarity of the presentation in the report. As I have said several times, there are no quibbles with the statistical analyses that have been done in the past. This has been challenged in the past. It was challenged by the Godfray Committee. I think those comments were taken on board at the time. No, there is not. In terms of R0, I do not follow Denis Mollison's arguments entirely, but I know he understands the concept of R0 as well as anyone else, including myself. I very much doubt there is any fundamental disagreement there.

  Q385  Sir Peter Soulsby: You respond to some of the criticism and dismiss it as mud-slinging but we did hear Professor Bourne describe your report as hastily written, superficial, selective, cherry picking and sound bites. Those are fairly serious criticisms from some people who have clearly given a lot of time and effort to looking at the science behind this. You must take that that criticism seriously, surely?

  Sir David King: If I had sent a paper in to be published and that was the referee's criticism, I would be very unhappy about it for the simple reason that it has not actually gone into the specific points of disagreement. It is the same comment as saying these people were not experts. I say: what is it that we are saying that is under attack and then we can address it? To make very general comments like that does not enable us to address the problems that may be seen.

  Q386  Sir Peter Soulsby: Looking back now at the way in which this has been handled, you spent a couple of days looking at a considerable body of research that had been published and peer reviewed over a considerable period of time. You spent a couple of days looking at it. I do not doubt the expertise of those who worked with you on it. You submitted it to the Secretary of State some months ago. You let those whose work you were criticising see this on Monday. Would you not accept that that is a somewhat inappropriate way of dealing with something as significant as this?

  Sir David King: I am in danger of repeating myself. Essentially we are not disagreeing with the 10-year study to which you have referred. The science in that study has been accepted by us in making our recommendations. If we ask a basic question that was the question that Krebs was asking—"Is there now evidence that badgers are a source of cattle TB?"—the answer is "yes". The Bourne committee makes that answer very clear and in some areas up to 40% of the incidence of TB in cattle herds can be attributed to badgers. I am quoting to you from that report, so I am not disagreeing with the science. I am simply taking the science with my colleagues and drawing a conclusion from that.

  Q387  Sir Peter Soulsby: Sir David, you keep telling us that you are not disagreeing with the science but it was very evident from the words I quoted from Professor Bourne and from the evidence he gave to us earlier, and indeed from the shaking of heads and the frowns that are going on behind you, that they certainly feel that you are seriously disagreeing with the work that they have done and the conclusions that they have drawn from it. There is a difference of opinion, a distinct difference of opinion. Would it not have been better for you to have discussed those differences of opinion with the original authors and then and only then to have produced a report of this sort?

  Sir David King: That is a very specific question which I can address. Would it not have been better to have discussed it with the authors? I was asked by the Secretary of State to provide him with advice so that he could ponder the issue. I deliberately brought in a small group of experts, and these are I want to stress experts who have substantial experience in the area of cattle TB, to help me to comment on this, but I stressed with those experts that it was for the Secretary of State to call when this would go public. That really is why I have not discussed it any more broadly than that.

  Lynne Jones: Would it not have been better for you to have discussed it off your own bat, purely so that you could have actually been more effective in producing this report to the Secretary of State?

  Chairman: We stand adjourned to go and vote.

  The Committee suspended from 4.09 pm to 4.18 pm for a division in the House

  Chairman: Sir David, you were going to give us your answer to the last question. We gave you a chance to think about it. If you have forgotten what it is we will move on and come back to it.

  Lynne Jones: I will tell you what it was: why did you not talk to Professor Bourne about your report? It is inconceivable, if you wanted to produce the best possible report using your challenging function, that you should not have done so unless you were prevented in some way. Were you?

  Q388  Chairman: Can I just add to that because, sitting here, when you are not a scientist or a statistician you have to try and make some sense of what two differing camps are saying about some data. Just to sum up, if I have understood correctly, what you have said is that the actual scientific findings, the results, if you like, of all the work in the randomised badger culling trials, and indeed the analysis of that which the ISG have produced over the last ten years, the block of data, if you like, the facts, where there is common ground, you do not disagree with, but you rather skilfully used the words to imply that there was quite a lot of agreement between the two of you by resting your case on, "We agree with the facts". What you have ended up doing is putting your interpretation of that information before us in your report, just as the ISG did with theirs, and we are now left as lay persons saying, "How do we find out which view is right?". I see the Minister nodding ruefully because he is going to be in the same boat as well. He can say, "I have now got the David King report, so that is all right; that is different", or he will get notes from his officials and various other luminaries in Defra who will write up lots of words of further advice, and the poor man has to make his mind up in order to make a recommendation to the Secretary of State. We have to write a report about this, but I think where Lynne Jones is coming from is saying is there any merit, before final decisions are made, in your group meeting with the former ISG to see if there can be, hopefully, some kind of meeting of minds rather than people administering knock-out blows to each other? What about it? Is there a chance of you getting together? It is amazing what you can do in a day and a half.

  Sir David King: I think, Chairman, that it is very important to establish the areas of agreement and the areas of disagreement and I wonder if I could just spend a few minutes on that.

  Q389  Chairman: Yes.

  Sir David King: For example, John and I were both interviewed on Radio 5 Live this week. He was asked, "If you really went for it and culled the badger would it work?", and his reply was, "Oh, yes, it would work partially. It would not be the complete answer to controlling the disease in cattle. It would probably contribute about 40% of the control and the other would have to rest with the cattle. David King is correct in saying that if you do not deal with the badger problem there will always be a residue of infection in cattle, that is absolutely true", so there is an area of agreement and I hope we can put that to one side. Where is the area of disagreement? I think if anything it comes round to the issue of how big an area you have to manage and over what period of time so as to get all of the positive effects associated with the badger cull. The negative effects are all in the periphery, are around the areas, so the larger the areas, the more hard boundaries you put on those areas—it is very clear from the data, and if I can just refer to page 105, figure 5.4 in the Bourne report, you will see that it is all shown very clearly there. By the time you get to 300 square kilometres with 95% confidence they are saying the cull would have a significant effect on reducing TB in cattle. Now the issue is one of practicality: is it possible to achieve these large areas? Is it possible to use hard boundaries? You will see if you read our report that we do not address those issues. These are issues that can be addressed by officials, so if the practical issues actually mean that this cannot be implemented, and if the economics are such that it goes against the report, then this would not disagree with what we are saying. Essentially we are saying—and I repeat this—that this is a massive problem in the farming community and it is a problem that is spreading over a relatively short timescale, and so it is time for hard decisions to be made. I am very keen to see that good attempts are made to look at these practical issues and that is what I am pressing for in this report.

  Q390  Chairman: As the Government's Chief Scientific Adviser you know that there are many scientific challenges which Government has to address. Do you monitor these areas of, if you like, science care planning? Were you as an individual watching, before the Secretary of State picked up his telephone to speak to you, what was happening in this area, before David Miliband said, "Produce this report"? Was it something that was on your radar?

  Sir David King: Yes, but in the sense that I have an office with about 90 people in it, a group of whom in my science in government team continually monitor issues of this kind, so the answer is, absolutely. The next question, if I may suggest it, is: and how do I prioritise how we spend our time in looking at data? Certainly, if a member of the Cabinet asked me to look at something that would be given priority.

  Q391  Chairman: Given that this was on your radar, had you indicated to any official in Defra before the Secretary of State rang you that this was something that was on your radar but something that you felt you would like to have a go at?

  Sir David King: I would be surprised if my officials had not done that, but for me to have a go at it, I think that would really require the Secretary of State to ask me to do that. In other words, I do not think I would have stepped in, but on the other hand I was hardly surprised.

  Q392  Chairman: You did not get a call from the Treasury saying, "We are spending £90 million a year. What can you suggest we do about it?"

  Sir David King: I did not actually get that call, but again I would not have been surprised if I had got it.

  Q393  Lynne Jones: If I could go back to my original question, you say that you do not disagree with the data, although you do question their statistical significance, and you do rubbish their ability to draw conclusions from their own data. In your paragraph 41 you say, "The data do not support such an unqualified conclusion", and in paragraph 42 you say, "The ISG view is unsound", so you have rubbished their view and I cannot understand why therefore you did not avail yourself of the opportunity of discussing it with them.

  Sir David King: We had the opportunity of the very detailed analysis they had presented and I would be very happy to send round copies of figure 5.4, page 105, of their report, which is the absolute basis of the comment I have just made.

  Q394  Lynne Jones: Sir John Krebs described the report as not providing any wriggle room in terms of their conclusions, so there are other people who have looked at it in a different light. I still do not understand why you did not talk with the ISG as part of your challenge function, such as the example that you gave to us at the very start when you challenged those scientists to go and look at the data.

  Sir David King: What I had in the case of the scrapie in sheep was a very different situation. I had for the first time, after a lengthy period of time, an unpublished report coming from that group of scientists and that was the reason I called them in. It would have been very improper of me to make a decision without calling them in. What I wanted to do was examine how robust their experimentation process had been and that is when I discovered that no DNA test had been conducted.

  Q395  Lynne Jones: I would have thought it would be even more the case that you would discuss it with these scientists who had had all their work and their conclusions peer reviewed. Anyway, we will move on.

  Sir David King: Chairman, I do think a bit much has been made about our statistical analysis and differences of opinion. We have had the various paragraphs being quoted at us. Our statement in paragraph 24, "This figure is on the borderline of statistical significance", is simply a statement from the report itself. We have used the error bars in our analysis given in the report itself, so we have not gone beyond the report; we have taken data directly from the report and simply used it in our report.

  Q396  Lynne Jones: But you have contradicted their conclusion. You have come to a diametrically opposite conclusion in terms of the practicalities of culling. If you were to have said, "Perhaps we ought at this time to try and address whether it is practical to have large area culling, certainly well above 100 square kilometres", which is certainly not a large area, "and a sustained programme over 10 years", there might have been something to discuss, but you have rubbished their conclusion and suggested 100 square kilometres.

  Sir David King: I cannot agree that their first conclusion follows from their data if you are simply taking a scientific view, absolutely. I am going to stand by that.

  Q397  Lynne Jones: You say their data does not support their conclusion and yet you did not take the trouble to discuss why it was that they had a different view from yourself.

  Sir David King: Because, shall I repeat, based on the scientific analysis there was no argument. We were simply saying that scientific analysis, based on the science alone. What they do mention are economics and practicality. When it comes to the science I am not, I repeat not, disagreeing with them, but their conclusion is not based on figure 5.4A on page 105 of their report and the other data.

  Q398  Chairman: Just to pick up on a point of Lynne's analysis, in Annex 1, "Confidence Intervals", you provide a commentary on the confidence intervals which the ISG have used and then you say at the end, "I consider that this level of precision may give the impression of more certainty than is the case".

  Sir David King: Yes. This is me speaking as a scientist, Chairman. I have always said to my students, "If you come to a figure of 34.7 and the error bar is plus or minus 15 then putting the decimal point, 34.7, is incorrect; it is misleading". That was just my statement. Statistics drop the decimal point; it is 35 plus or minus 15 in that case, so if you like that was just me making my own statement.

  Q399  Chairman: But you are writing this document to an outside world that deals with language.

  Sir David King: Yes.

  Chairman: And there is another group of people who deal with statistics and scientific findings, and it is like all propositions: people look at them from different standpoints and come to different conclusions according to the way that they are presented and expressed; hence the line of questioning that we are following up.


 
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