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enzer and Edwards, 2003; Gigerenzer and Hoffrage,
2007). In reality, it may be challenging for veterinarians
to differentiate between evidence of varying strength
and quality. Other factors, such as the perceived repu-
tation of the scientists conducting the work, the final
concluding remarks of the paper, or the point estimate
alone (not in combination with the confidence or cred-
ible interval) may be more influential. More research is
needed to establish how logically veterinarians update
their beliefs about clinical parameters, using informa-
tion published in veterinary journals. This is important
to ascertain, because investing money in larger clinical
trials to convince skeptical clinicians will not provide
a return unless they revise their beliefs in at least a
somewhat logical manner. And, of course, due consid-
eration should be given to all the other factors that
influence veterinary beliefs and other approaches em-
ployed as necessary. This could include communication
strategies, as well as helping veterinarians to interpret
new information appropriately, and facilitating and im-
proving veterinary education (both undergraduate and
postgraduate).
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Heuristics and biases. Science 185:1124–1131.
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It is also worth noting that, in human medicine, λ
has not been elicited from doctors, even though doc-
tors’ clinical demands have been elicited. A choice for
λ that is less than 0.95 may not be generally accept-
able to the scientific community, because it may not be
regarded as robust enough evidence. However, it is a
subjective choice and clinically useful information may
go unreported if only clinical trials achieving λ ≥0.95
are published.
A potential limitation of this study is the repeat-
ability of the results at a later date in the absence of
any genuine change in veterinarians’ beliefs. There is
no literature reporting the repeatability of the method.
However, during the interviews, extra clarification was
given if required. This reduced misunderstanding, which
is one reason why different results may be obtained on
different dates.
APPENDIX
Standard Elicitation Script
Clinical Expectations: Mastitis Intervention.
My first question is about a clinical mastitis interven-
tion and how successful you think it might be when
implemented on a large number of dairy farms.
Please imagine that all the dairy farms in England
are visited by their own local veterinarian today, spe-
cifically to discuss their current clinical mastitis situ-
ations. As a result, we have identified a large number
of farms, for which both the farmer and their local vet
have agreed there is a clinical mastitis problem and
they have decided that the farmer will go ahead with a
structured clinical mastitis intervention with the help
of their local vet over the next year.
By a structured clinical mastitis intervention over the
next year, I mean the following:
ACKNOWLEDGMENTS
Initially, the vet tries to identify the main cause (s) of
the mastitis problem. The vet carries out some strategic
laboratory testing, assesses any available milk recording
data and any other relevant farm data that is available
(e.g., clinical mastitis records). The vet then makes a
specific visit to walk round the farm and assess the
risks that may be contributing to the problem. The vet
quantifies the risks using our current best evidence for
clinical mastitis. As a result the vet produces a list of
recommendations, prioritizes them and discusses them
with the farmer. Over the next year, the vet revisits the
farm at least every quarter, reassesses any data avail-
able and the on-farm risks, and modifies the recom-
Our thanks go to all the veterinarians who partici-
pated in this study. H. M. Higgins was funded by a
Wellcome Trust Research Fellowship [087797/Z/08/Z]
and hosted by the University of Nottingham, UK.
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Journal of Dairy Science Vol. 97 No. 6, 2014