The Delphi method is a systematic, interactive forecasting method which relies on a panel of experts.1 On the assumption that group judgments are more valid than individual judgments the experts answer questionnaires in two or more rounds. After each round, a facilitator provides an anonymous summary of the expert’s forecasts from the previous round as well as the reasons they provided for their judgments. Thus, experts are encouraged to revise their earlier answers in light of the replies of other members of their panel. The initial contributions from the experts are collected in the form of answers to questionnaires and their comments to these answers. The panel director controls the interactions among the participants by processing the information and filtering out irrelevant content. It is believed that during this process the range of the answers will decrease and the group will converge towards the “correct” answer and, at the same time, it avoids the negative effects of face-to-face panel discussions and solves the usual problems of group dynamics.
In this issue of Allergologia et Inmunopathologia2 we can see an application of the method to two different documents related to paediatric asthma: The Consensus Document on the Management of Childhood Asthma and the 2009 Spanish Guideline on the Management of Asthma (GEMA 2009).3,4 We would like to stress some aspects of these two documents.
AcceptanceThere are areas such as science and technology where the degree of uncertainty is so great that exact and always complete consensuses are impossible, so a high degree of error is to be expected. On the basis of clinical evidence it becomes easier for experts to reach a good level of agreement, so it is important to establish the points in which the opinions have to be based. Fortunately in medicine the grade of evidence is a well-known subject which is widely accepted and categorised. According to these grades of evidence the questions were answered and classified. In one of the studies there was a direct participation of an institution (South America Cochrane Center) devoted to ensuring that the methodological procedures seeking the evidence, were the correct ones. Overall this approach ensures a high level of acceptance by the professionals.
RelianceIt is said that a particular weakness of the Delphi method is that future developments are not always predicted correctly by the consensus of experts. Firstly, as we stated before, the amount and quality of the previous information is of capital importance. If panellists are misinformed about a topic, the use of Delphi may add only confidence to their ignorance. Secondly, sometimes unconventional thinking of amateur outsiders may be superior to expert thinking. In this aspect, taking into account the panellists who were engaged in its elaboration, the two studies show an impressive consistency. The first document is born from the consensus of five paediatric associations, and the second is the result of the consensus agreement of nine scientific associations, including the Spanish Society of Paediatric Pneumology and the Spanish Society of Paediatric Allergy and Clinical Immunology. A very important point, as stated by the authors, is that paediatric asthma is not focused as a special situation within asthma but as a dynamic entity with a thorough approach on different situations of diagnosis and treatment.
Positive feed backWhile in regular group meetings participants tend to stick to previously stated opinions and often conform too much to the group leader, this method prevents such a situation and participants can revise their earlier positions at any moment.
We can observe that this occurred with respect to the most controversial points: the treatment of children under 3 years of age, and the role of immunotherapy in allergic asthma.
While in the first round there was a similar rate of agreement in both documents (80.7% and 87.5%) it was not until the second round that some particular items did not reach a consensus. Of particular importance was the grade of agreement on the immunotherapy treatment, comparing the two documents. The results of the first document, even prone to establishing a positive role of this procedure, are not as conclusive as the second one. Assuming that the question was, more or less, the same, it becomes clear that some statements which one may not completely agree with were accepted on the basis of scientific evidence. Additionally, as the authors say “it underlines the importance of guidelines and consensus documents for unifying criteria supported by scientific evidence and strength of recommendation”.
To conclude, in our opinion, the results obtained in these two studies clarify and help to make the subject of Paediatric Asthma, more tangible, approachable, and reasonable.
