Three rounds, which would typically take four months, often suffice (Stone Fish & Busby, 2005). However, this approach can quickly compromise panellists’ response rates and enthusiasm. When exploring consensus, rounds may continue until consensus is reached. Also, the reliability and validity of the study may be improved if an initial group of experts produces the items. Although quantitative questionnaires have been used in the first round, a qualitative first round is optimal, because the primary function of the Delphi method is to explore an area of future thinking that goes beyond the currently known or believed. Petry et al., 2007) is most suitable when there is a clear literature base from which to establish the survey instrument and if the main aim is to take the temperature of opinion on a topic. letters to participants, consent forms, complete ethics procedures).Ī two-round Delphi (e.g. The next step is to decide the number of rounds, to draw up a timeframe and to construct study materials (e.g. Having a complete dataset is less vital, and the panel can be expanded across rounds by inviting more panellists in Round 2. On the other hand, if the Delphi process is a means of measuring opinions, fewer rounds are generally acceptable. Ideally, the same panel should be retained throughout and high response rates are particularly important in order to determine the impact of group feedback on panellists. In general, if your study aims to generate consensus, three or more rounds are preferable. This is an important distinction in terms of the execution of the Delphi. The first step is to determine whether the study aims to measure the diversity of opinions on a topic or to steer a group towards consensus. It is not an exhaustive account, and further guidance is available elsewhere (e.g. To make the Delphi method more accessible for psychologists unfamiliar with this method, this article provides a practical step-by-step guide based on our experiences of conducting Delphi studies in clinical psychology. However, the many applications and descriptions available in the literature can be confusing, and the Delphi method, with a few exceptions, remains relatively unexploited in psychological research (e.g. The Delphi method is particularly useful in areas of limited research, since survey instruments and ideas are generated from a knowledgeable participant pool (Hasson et al., 2000), and it is suited to explore areas where controversy, debate or a lack of clarity exist. I It is interested in the formation or exploration of consensus, often defined as the number of panellists agreeing with each other on questionnaire items. I It has an evaluation phase (third or further rounds) where panellists are provided with the panel’s responses and asked to re-evaluate their original responses. I It collates ideas from Round 1 to construct the survey instrument distributed in subsequent rounds.
It employs an initial ‘idea generation’ stage, in which panellists are asked to identify the range of salient issues.
Delphi method series#
I It is often conducted across a series of two or more sequential questionnaires known as ‘rounds’. I It uses a group of participants (known as ‘panellists’) specially selected for their particular expertise on a topic. Although there is considerable variation in how the method is applied, the Delphi method has its own distinct characteristics: