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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