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Methods Moment: The Delphi Method

Tenley Sablatzky, MLISa

aMedical Librarian, Undergraduate Medical Academy, Prairie View A&M University,
Prairie View, Texas, https://orcid.org/0000-0001-5656-3206 , tnsablatzky@pvamu.edu,

Twitter

Method Name(s): The Delphi Method

Description: The Delphi method is a process used to arrive at a group opinion or decision
by surveying a panel of experts. The method was developed in the 1950’s and 1960’s by the
RAND Corporation and since then has been used in many fields, including library and
information science. During a Delphi study, selected experts respond to several rounds of
questionnaires, and the responses are aggregated and shared with the group after each round.
A Delphi study relies on the idea that collective group responses are superior to individual
responses.

Purposes: Originally the Delphi method was created as a systematic, interactive forecasting
method relying on a panel of experts. Since then, Delphi studies have been used for many
purposes: creating policy, establishing guidelines, and identifying trends.

Overview

The Delphi Method is a survey technique used to gain a consensus of a panel of experts in
the field through several rounds of questioning. The method was developed during the 1950s
and 1960s by the RAND corporation to prepare for national security threats during the Cold
War. Since then, it has been used as a research method in a variety of fields, including
marketing, advertising, education, and medical science. Other fields, including library and
information science, began incorporating the method into their research during the 1970s1. A
typical Delphi study consists of multiple rounds of written questionnaires sent to identified
experts. After each round, the facilitator collects and reviews the data and distributes a
summary report to each expert who then reviews the report and either agrees or disagrees
with the other experts’ answers. This cycle continues until a consensus is reached.

The justification for performing a Delphi study lies in the theory that collective group
responses are superior to individual responses. The theory suggests that even the most
qualified, well-researched individual may have ideas that are not “the best”, but when
considered as a collective, the best ideas tend to elevate to the top. Niederberger and
Spranger’s 2020 article2 explains that in some fields, such as technical and natural sciences,
the Delphi method is used to analyze future developments; other fields, like the health
sciences, use it for reaching a consensus. In library and information science, Delphi studies
have proven to be a popular research method; library science researchers have used Delphi
studies to answer questions, including what are the best practices for collection development
or information literacy instruction3. For example, in 2009, a Delphi study about the Medical
Library Association’s (MLA) research agenda was published in The Journal of the Medical
Library Association4. Delphi studies are valid techniques even though they are considered a
lower level of evidence than meta-analyses or correlation studies. Because of this, Delphi
studies are less suited for research questions about intervention effectiveness and more suited
for questions about practices or trends. Often, the results of a Delphi study are used to draft

1

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https://orcid.org/
mailto:tnsablatzky@pvamu.edu
https://twitter.com/tenleynadine


Peer Reviewed Article Hypothesis , Vol. 34, No. 1, 2022

Figure 1: The step-by-step process of conducting a typical Delphi study

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Peer Reviewed Article Hypothesis , Vol. 34, No. 1, 2022

white papers, techniques, or guidelines. They can also be used as a preface to another
research method.

Carefully selecting a team of knowledgeable experts who are well-versed in at least one aspect
of an issue is the most critical step of a successful Delphi study. The team of experts does not
need to be representative of every population, but the selected qualified participants should
be knowledgeable of the issues and viewpoints related to the topic being studied. The
strengths, weaknesses, and biases of the expert panel will determine the strengths, weaknesses
and biases of the findings. Okoli and Pawlowski’s 2004 article designates the selection of
experts as the most critical step of a Delphi study. For their study, they carefully determined
the research questions they were trying to answer and then designated four distinct groups of
experts that would be beneficial to include in their study design: academics, practitioners,
government officials, and officials at non-profit organizations5. The types of experts required
varies depending on the research questions, but the initial determination of who will be part
of the panel is critical to creating a study with minimal bias and viewpoints representative of
the whole community.

As the Delphi method is a survey technique, bias is a common limitation that researchers
need to be aware of and carefully consider. Melander’s 2018 article explains that desirability
bias is a major limitation of Delphi studies. The article notes that desirability bias, or
social-desirability bias, means survey respondents tend to answer questions in a manner that
will be viewed favorably by others or lean towards a favored projected outcome6. A
straightforward approach to minimizing desirability bias is simply to include survey questions
asking the experts to rate the desirability of their projections. By doing so, the researcher is
able to reflect on and account for desirability bias in the study as much as possible. The most
common way of minimizing bias in the broader consensus is to ensure that experts are diverse
and that they have been chosen based on their expertise and in reference to the research
question(s).

The best way to select a diverse group of qualified experts is for the researcher to take time
at the start of their study to create a balanced Knowledge Resource Nomination Worksheet
(KRNW). A KRNW is a helpful tool for identifying the necessary experts for a study (see
Figure 27). The first step, as defined by Okoli and Pawlowski, is to create a list of the
necessary disciplines and skills, relevant organizations, and relevant literature needed for the
research study5. The initial list is populated with the names of specific individuals at relevant
organizations, or authors who have published relevant work on the subject matter. In the
next step, the researcher should begin contacting individuals who have been identified. In
addition to inviting these individuals to be part of the panel, the researcher may ask for the
recommendation of additional experts. Once a list of experts willing to serve on the panel has
been created, the experts are then categorized based on their qualifications and expertise.
The target size for an expert panel will vary depending on the expertise required, though
Sekayi and Kennedy, in their 2017 article, suggest that twenty to thirty panelists is ideal for a
Delphi study. If more than thirty experts are used, then the process may become too
unwieldy and repetitive to be of any real value8. The average Delphi study consists of two or
three rounds of surveys and typically takes four to six months to complete.

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Peer Reviewed Article Hypothesis , Vol. 34, No. 1, 2022

Figure 2: The process of creating a Knowledge Resource Nomination Worksheet.
Adapted from Okoli and Pawlowski.7

The major strength of performing a Delphi study, as noted in Lund’s 2020 article, is that no
one subject can dominate the conversation, as can sometimes happen in a focus group3.
Responses to Delphi surveys that are less popular to the group of experts will be eliminated
during the process, as opposed to a traditional survey where all responses are given equal
weight. The major weakness, however, arises when the researcher conducting a Delphi study
does not want to eliminate responses that are less popular. Lund explains that the researcher
may consider these less popular responses to be important pieces of data because, while they
are not common, still represent some of the total responses3. However, in a Delphi study it is
not ethical to use researcher’s personal preferences for a less popular piece of data to sway the
trajectory of the study. The strength of a Delphi study is the focus on consensus agreements
among available experts. If a researcher needs to consider all viewpoints equally to
adequately answer their research questions, a Delphi study is not the ideal study design for
the project. Delphi studies are best used in situations where the collective group responses
are superior to individual responses.

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Peer Reviewed Article Hypothesis , Vol. 34, No. 1, 2022

Example

Rarian, an instructional librarian, needs to develop assessment guidelines to determine the
success of their first-year information literacy class. Being new to the job, they are unsure of
the best way to measure the students’ learning. After doing some online research, Rarian
discovers that there are different instruction assessment methods used by librarians but no
clear answer exists about which one is the most effective. Rarian speaks to a colleague for
advice on the best course of action. Their colleague agrees that the research does not show a
consensus on the best practices for assessment, and suggests that performing a Delphi study
could be a helpful starting place. Being unfamiliar with the term, Rarian asks for
clarification, and their colleague proceeds to explain the basic mechanics of Delphi study.
Rarian agrees that receiving input from a diverse panel of experts would be beneficial for
determining the most common methods of assessment and reaching a consensus on the most
effective methods. Rarian and their coworker decide upon the following research question:
What methods of assessment are most effective for information literacy instruction sessions?

Knowing that the selection of experts will be critical to the success of the study, Rarian takes
the time to prepare a Knowledge Resource Nomination Worksheet (KRNW) to identify
qualified experts. The first step is to determine how to categorize the backgrounds and
subject areas required before selecting participants. Rarian creates a chart listing the skills
and disciplines necessary, and also notes libraries and educational organizations with potential
experts. With the list in hand, they begin searching for and contacting individuals with the
necessary skills and populating the KRNW with names. Rarian is also sure to ask the
recruited experts to nominate additional experts who could be an asset to the project.

Once Rarian has twenty-five confirmed experts to participate in the study, they begin
drafting the first survey. For the first round of questions, Rarian focuses on asking general
questions to gain a broad understanding of the types of assessments the experts used and
which they found most effective. As the surveys progress, the questions become more specific,
based on the past responses. For example, after noting in the first round that a significant
number of experts mentioned course surveys as an assessment method, they were sure to
include questions in round two regarding the types of questions, survey length, and
distribution method of the survey. Rarian uses the strongest answers from the second round
to create a summary report for the experts and a new questionnaire. The experts then rate
and comment on the third set of assessment methods with guidance from the information in
the report of the previous round. After the third survey, Rarian has narrowed the questions
enough to receive a consensus on the most effective form of assessment for library instruction.
Next, Rarian writes up and further analyzes their findings by testing the selected assessment
method in the classroom. After testing the results, they may find that further study or an
additional research method is necessary. In some cases, this can lead to a second Delphi study
with a different panel of experts; in other cases, a different research method will be required
to expand the research.

Resources

Delphi technique a step-by-step guide [Internet]. Project Smart. Project Smart; 2021 - [cited
2022 Jul 11]. Available from:
https://www.projectsmart.co.uk/tools/delphi-technique-a-step-by-step-guide.php

What is DELPHI METHOD? What does DELPHI METHOD mean? DELPHI METHOD
meaning, definition & explanation [Internet]. YouTube. Audiopedia; 2017 [cited 2022 Jul 11].
Available from: https://www.youtube.com/watch?v=0ap77w8FKYM

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https://www.projectsmart.co.uk/tools/delphi-technique-a-step-by-step-guide.php
https://www.youtube.com/watch?v=0ap77w8FKYM


Peer Reviewed Article Hypothesis , Vol. 34, No. 1, 2022

Delphi method [Internet]. RAND Corporation. The RAND Corporation; [cited 2022 Jul 11].
Available from: https://www.rand.org/topics/delphi-method.html

Further Reading:

Fletcher, A. J., Marchildon, G. P. Using the Delphi Method for qualitative, participatory
action research in health leadership. International Journal of Qualitative Methods. 2014 Feb
1;13(1):1–18.

Hasson, F. Research guidelines for the Delphi survey technique. Journal of Advanced
Nursing. 2008 June;32(4):1008-1015.

Mozuni, M., Jonas, W. An introduction to the morphological Delphi Method for design: A
tool for future-oriented design research. She Ji: The Journal of Design, Economics, and
Innovation. 2017 Dec 2017;3(4):303–318.

Rabina, D. Reference materials in LIS instruction: A Delphi study. Journal of Education for
Library and Information Science. 2013 Apr 1;108-23.

Townsend, L., Hofer, A., Lin Hanick, S., Brunetti, K., University of New Mexico, University
Libraries. (2016). Identifying threshold concepts for information literacy: A Delphi study.
Communications in Information Literacy. 2016 June 6;10(1):1.

References

1. Ju B, Jin T. Incorporating nonparametric statistics into Delphi studies in library and
information science. Information Research: An International Electronic Journal. 2013
Sep;18(3):n3.
2. Niederberger M, Spranger J. Delphi technique in health sciences: A map. Frontiers in
Public Health. 2020 Sep 22;8:457.
3. Lund BD. Review of the Delphi method in library and information science research.
Journal of Documentation. 2020 Feb 28.
4. Eldredge JD, Harris MR, Ascher MT. Defining the Medical Library Association research
agenda: Methodology and final results from a consensus process. Journal of the Medical
Library Association: JMLA. 2009 Jul;97(3):178.
5. Okoli C, Pawlowski SD. The Delphi method as a research tool: An example, design
considerations and applications. Information & Management. 2004 Dec 1;42(1):15-29.
6. Melander L. Scenario development in transport studies: Methodological considerations and
reflections on Delphi studies. Futures. 2018 Feb 1;96:68-78.
7. Okoli C, Pawlowski SD. The Delphi method as a research tool: An example, design
considerations and applications. Information & Management. 2004 Dec 1;42(1):15-29.]
8. Sekayi D, Kennedy A. Qualitative Delphi method: A four round process with a worked
example. The Qualitative Report. 2017 Oct 1;22(10):2755-63.

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https://www.rand.org/topics/delphi-method.html

