Delphi Method Explained: Key Uses in Scientific Research

The Delphi method is considered one of the most important research methods in qualitative studies, as it provides an organized approach to reaching a reliable group opinion through consulting experts in successive rounds of evaluation. This method has gained its position for its ability to gather specialized knowledge, reduce biases, and generate accurate predictions regarding complex issues that are difficult to measure using traditional methods.

Delphi is based on methodological steps that include distributing questionnaires, providing feedback, and re-evaluating to reach a degree of scientific consensus. In this article, we review the concept of the Delphi method and how to use it in scientific research, explaining its importance, application areas, as well as examples from Arabic and international research that have utilized it.

What Is the Delphi Method? and Why Was It Named This Way?

The Delphi method is a research method that relies on gathering expert opinions through repeated rounds of questionnaires to reach a group agreement on a specific issue. It was named after the Greek city of Delphi, which was historically famous for its center of prophecy and wisdom, reflecting the method’s nature of forecasting and decision-making based on specialists’ experiences.

What Are the Characteristics of the Delphi Method in Research?

The Delphi method is based on a set of methodological principles that aim to ensure the quality of opinion collection, reduce biases, and achieve group consensus based on scientific expertise rather than social influences. These principles form the foundation that gives the method its ability to produce accurate and usable knowledge for prediction, decision-making, and developing research policies.

1- Principle of Expert Independence

The Delphi method involves experts who work independently without direct communication with each other. This principle aims to prevent the influence of status or scientific authority within the group, ensuring that answers stem from pure individual analysis that reflects each participant’s experience.

2- Principle of Organized Repetitive Rounds

The method is built on implementing several rounds of questionnaires, during which experts have the opportunity to review their previous opinions based on group results. This repetition allows for improving the quality of answers and gradually reducing dispersion until a clear group direction emerges.

3- Principle of Neutral Feedback

After each round, participants receive a summary of previous responses showing opinion averages and consensus directions without revealing expert identities. This principle ensures that feedback is objective and neutral, supporting the scientific re-evaluation of opinions.

4- Principle of Gradual Consensus

The Delphi method does not rely on a final direct vote, but on building gradual consensus that appears through opinion stability across rounds. When differences between answers narrow and show similar repetition, this is considered an indicator of achieving scientific consensus.

5- Principle of Confidentiality and Non-disclosure of Participants

The method maintains the confidentiality of expert identities to ensure process neutrality and prevent personal or social influences. This principle helps create a fair scientific environment that encourages honesty and reduces formalities or pressures.

These principles make it an effective method for organizing group thinking and transforming multiple experiences into a unified scientific opinion. These principles reflect the value of Delphi as a flexible and reliable method in qualitative studies and future forecasting.

Steps to Apply the Delphi Method Step by Step

The Delphi method is applied within a gradual methodological path that begins with the decision to use it and ends when reaching an acceptable degree of consensus among experts and including the results in the final study structure. The strength of this method lies in that each step prepares for the next through organized feedback, transforming scattered individual opinions into a mature group opinion that can be used in planning, decision-making, and scientific research. This path includes a set of methodological steps:

1- Preparing the Study and Determining the Objective of Using the Delphi Method

The application process begins with identifying the research problem or the issue under study, and formulating a clear objective for using the Delphi method, such as forecasting future trends, determining priorities, or building a list of criteria. At this stage, the researcher decides whether Delphi is the most appropriate method, and defines the scope of the topic and its main axes that will form the basis for subsequent rounds.

2- Selecting Experts and Criteria for Including Them in the Sample

This is followed by identifying the category of experts on whom the entire process will be based, by establishing clear criteria for scientific and practical expertise in the studied field. The researcher ensures diversity in experts’ specializations and balance in their backgrounds, while emphasizing their independence and absence of conflicting interests, as the quality of outputs is directly related to the quality of this sample.

3- Designing the Initial Questionnaire and Formulating Its Axes

Designing the first round instrument is a crucial step, as it translates the research problem into questions or statements that encourage experts to express their opinions freely. The topics are often formulated as open-ended questions or broad evaluation statements that allow for the collection of the maximum number of ideas, which are later used to develop more specific items in subsequent rounds.

4- Implementing the First Round and Collecting Responses

The initial questionnaire is sent to experts with a brief explanation of the study’s objective and the nature of the Delphi method along with confidentiality constraints. A suitable time period is given for responses, which are then collected as-is without direct discussion among participants, ensuring independence of opinion and preventing mutual influence or dominance of stronger voices.

5- Analyzing the First Round and Building Feedback

After collecting responses, the researcher conducts qualitative or quantitative analysis to extract recurring ideas, general trends, and points of disagreement. In this stage, organized summaries representing the group’s opinion without mentioning names are produced, and these summaries are used as the basis for building a more specific questionnaire in the second round.

6- Preparing Subsequent Rounds and Modifying Items

The questionnaire is reformed based on the analysis results, making the items more focused and potentially converting them into evaluable statements (such as Likert scales) to measure the degree of agreement. The second round is sent to experts accompanied by brief feedback on the first round’s results, allowing each expert to review their position in light of the group’s opinion and modify their responses if deemed appropriate.

7- Continuing Rounds Until Consensus Is Reached

The process is repeated in successive rounds as needed, with continued feedback provided after each round and modification of items to enhance clarity and reduce dispersion. The number of rounds typically stops when results show stability in responses or an acceptable level of statistical or qualitative consensus, such that new rounds would not add substantial value.

8- Documenting Results and Integrating Them Into the Study Framework

In the final stage, Delphi method results are presented in tables and analytical interpretations that explain the degree of consensus, elements agreed upon or disputed, and how these outputs are used to answer research questions or formulate recommendations. The selection procedures, rounds, and stopping criteria are also documented to make the method evaluable and replicable in subsequent studies.

The true value of this methodological path for applying the Delphi method lies in its ability to transform scattered individual expertise into an organized collective opinion that can be relied upon to guide research and practical decisions systematically and rigorously.

When Is the Delphi Method Used?

The Delphi method is used in contexts that require future estimation or expert judgment on issues for which clear data is not available, as it involves collecting opinions from a select group of specialists through multiple rounds to reach cognitive consensus. This method is suitable for topics characterized by complexity and intertwined factors, with the most prominent being:

1- Forecasting Future Issues

The method is used when institutions need to estimate future trends such as technological or economic transformations. This approach allows integration of multiple experiences to form a shared vision of development possibilities. It is particularly suitable in cases of data scarcity or rapidly changing environments.

2- Supporting Decision-making in Uncertain Environments

Delphi is employed when decision-making cannot rely solely on quantitative evidence. It allows for collecting expert opinions on multiple options with analysis of strengths and weaknesses. It holds particular importance for sensitive strategic decisions.

3- Building Public Policies Based on Expert Opinion

Policymakers turn to Delphi when decisions require foresight into social, educational, or health practices. The method contributes to producing a knowledge framework that helps regulate public interventions. It reduces risks of decisions based on individual estimates.

4- Developing Academic Curricula and Programs

Educational institutions use this method to identify future skills and develop curricula better aligned with the job market. It allows collection of expert opinions in multiple rounds to reach a shared understanding of core content. This contributes to ensuring development quality.

5- Studies Involving Multiple Disciplines

The method is beneficial when the phenomenon requires a multi-dimensional perspective, such as cybersecurity or digital transformation issues. It helps overcome disciplinary bias by integrating analyses from experts in different fields. This leads to more balanced results.

6- Evaluating Complex Risks

Delphi is used to assess risks that are difficult to measure with traditional tools, such as environmental or technical risks. The method relies on integrating specialized expertise to transform risk assessment into a relative quantitative vision. It helps in developing response plans.

7- Long-term Planning in Organizations

Advantages of the Delphi Method

The Delphi method is considered an interactive research method based on gradually and systematically collecting expert opinions. It is used in environments that require future assessment or decision-making with incomplete information. This method is based on the principle of systematic repetition aimed at reducing bias and achieving objective consensus among a group of specialists. Below are its main essential advantages within the methodological and research framework:

1. Enhancing group objectivity by integrating opinions from multiple experts without direct influence between them.
2. Reducing power and expertise bias through the confidentiality of participation and the absence of direct confrontation.
3. Providing a gradual review of opinions, which allows for re-evaluating positions based on emerging consensus.
4. Improving the accuracy of future predictions through repeated rounds to refine expert estimates.
5. High suitability for complex topics requiring multi-dimensional perspectives.
6. Flexibility in application through electronic means that facilitate global participation without time or geographical constraints.
7. Production of more stable data due to reduced variation in estimates with each round.
8. Ability to support institutional decision-making by formulating a convergent, reliable expert opinion.

Thus, the Delphi method provides a methodological framework capable of producing accurate collective knowledge, making it a prominent choice in foresight studies and research requiring highly reliable expert consensus.

Disadvantages and Challenges of the Delphi Method

The Delphi method is viewed as an effective research tool in generating expert consensus, but its application is not without disadvantages and challenges that affect its reliability if not managed with precise methodology. These challenges stem from the nature of relying on experts and from the repetitive structure that may lead to biases or variations in data quality. Below are the main disadvantages and challenges associated with this method:

1. Potential decrease in result quality when selecting unqualified experts or those with limited experience in the field.
2. Prolonged study duration due to the need for multiple rounds to reach acceptable consensus.
3. Risk of forced similarity of opinions resulting from participants’ tendency to formal conformity rather than scientific conviction.
4. Impact of response rates, as expert withdrawal or weak commitment weakens overall reliability.
5. Potential for questionnaire design bias if questions are not constructed in a neutral and objective manner.
6. Variation in experts’ interpretation of questions, creating unintended variation in the nature of responses.
7. Heavy reliance on the skill of the study coordinator in managing rounds and controlling analysis quality.
8. Limited ability to generalize, as results typically reflect the views of a specific group of experts rather than a broad population.

Therefore, managing the Delphi method requires a high degree of precision in selecting experts, designing rounds, and analyzing data to ensure obtaining scientific outputs with reliability and methodological consistency that can be built upon in future studies.

Advanced Methods Derived from Delphi

The Delphi method has evolved over time to include more advanced models that respond to contemporary research needs, particularly in decision-making, foresight, and public policy design. These derived methods are characterized by maintaining the essence of Delphi, which is based on gradual consensus among experts, while adding analytical or interactive mechanisms that give the process greater accuracy and depth.

1- Modified Delphi

This method relies on providing experts in the first round with a predefined list of themes or phrases extracted from scientific literature or previous studies, instead of traditional open-ended questions. This modification aims to reduce time and improve focus, especially in studies with a clear knowledge base, allowing for a faster transition to measuring consensus.

2- Weighted Delphi

This model is used when experts have different levels of expertise or scientific influence, where their answers are given varying weights according to specific criteria such as years of experience or academic degree. This method provides a more realistic picture of consensus because it balances opinions based on their scientific value rather than just the number of votes.

3- Real-time Delphi

This model combines the advantages of traditional Delphi and modern digital technologies, allowing experts to interact in real-time through an electronic platform that displays feedback immediately after answers are entered. This system reduces the time required for rounds and increases interaction accuracy without sacrificing the principle of anonymity or consensus.

4- Multi-criteria Delphi

This method is used when the subject requires evaluating multiple elements simultaneously, such as prioritizing projects or choosing between strategic alternatives. It combines Delphi with multi-criteria decision-making techniques, enabling experts to evaluate each element according to precise weights and methodological criteria.

5- Mixed Delphi

It combines qualitative and quantitative aspects in one method, using open-ended questions in the first rounds to generate ideas, then converting these outputs into quantitative measures in subsequent rounds to measure the degree of consensus. This model is one of the most suitable derivatives for complex studies that require both interpretation and numerical analysis at the same time.

6- Futuristic Delphi

This method focuses on foresight through scenario analysis, trends of change, and identification of potential driving factors. It is suitable in strategic planning, technology studies, education, and public policy, as it places expert opinions within a future time frame rather than just the current situation.

These advanced methods derived from the Delphi method provide flexible methodological options that enable the researcher to choose the most suitable version

for their research problem, while maintaining the essence of Delphi based on gradual and systematic scientific consensus.

Tips for Successfully Applying the Delphi Method in Scientific Research

Applying the Delphi method represents a precise methodological step that requires careful planning to ensure reaching a reliable and research-usable expert consensus. The importance of these tips stems from their role in enhancing the quality of the interactive process among experts, strengthening the rigor of analysis, and reducing bias that may arise through repeated rounds. Below are the most prominent tips that contribute to the successful application of the Delphi method in scientific research:

1. Select experts with genuine experience in the field to ensure the quality of shared knowledge.
2. Design neutral and accurate questionnaires that focus on essential points without influential expressions.
3. Formulate measurable and analyzable questions to facilitate comparison between rounds.
4. Provide uniform methodological instructions for all participants to ensure a similar understanding of the questions.
5. Maintain answer anonymity to prevent influence from personal opinions or academic status.
6. Pre-determine the number of rounds with slight flexibility to adjust the course as needed.
7. Analyze data using clear statistical criteria to track stability in opinions.
8. Provide structured feedback between rounds that highlights trends without imposing a specific interpretation.
9. Ensuring effective time management to guarantee continuous participation of experts in all rounds.
10. Using reliable electronic tools that ensure ease of participation and accurate data collection.
11. Ensuring a balanced sample size of experts sufficient to represent diverse opinions.
12. Documenting analytical criteria in advance to enhance transparency and methodological consistency.

Thus, adherence to these guidelines enhances the interpretive strength and scientific reliability of Delphi method results, making it an effective tool in foresight studies and knowledge-based decision making.

Examples of Scientific Research That Used the Delphi Method:

The Delphi method is widely used in research requiring collective expert opinion, especially in fields where quantitative data is difficult to rely on or where future predictions or standard development is required. The following applications show how researchers have leveraged the power of Delphi in developing knowledge and scientific decision making:

Example 1:

Research titled ‘Perceptions of education experts on the requirements for activating future studies in educational research: A study using the Delphi method’

Researchers: Dr. Najla Muhammad Al-Hadheef and Prof. Ibrahim Abdullah Al-Obaid

The study aimed to identify the perceptions of education experts regarding the human, methodological, and procedural requirements for future studies in educational research, and to achieve its objectives, the study used one of the foresight research methods: the Delphi method.

Example 2:

Research titled ‘Future forecasting for green human resource management in government intermediate schools in Riyadh using the Delphi method’

Researcher: Fatima bint Hamid Ali Al-Tuwayrqi

The study aimed to forecast the future of green human resource management in government intermediate schools in Riyadh using the Delphi method, and to achieve the study’s objective, one of the foresight research methods and future forecasting was used: the Delphi method.

Example 3:

Research titled ‘Future challenges in implementing artificial intelligence in guidance and counseling programs using the Delphi method’

Researcher: Abdullah Ghali Majoul Al-Saeedi.

The study addresses future challenges in implementing artificial intelligence techniques in guidance and counseling programs with the aim of identifying technical, ethical, and social obstacles that may hinder the development of these applications. The researcher relied on the Delphi method as a foresight methodology that allows collecting opinions from experts (student counselors) in three consecutive rounds to achieve consensus on potential challenges.

Example 4:

Research titled ‘Management of adult sepsis in resource-limited settings: global expert consensus statements using a Delphi method’

Researchers: (Thwaites, et al)

The study aims to reach consensus and provide specialized clinical practice data for managing adult sepsis in resource-limited settings. The study methodology was based on forming the Asia-Pacific Sepsis Alliance (APSA) as an international multidisciplinary steering committee experienced in sepsis management, including an expert in Delphi methodology. The committee selected an international team of clinicians and researchers experienced in sepsis management. The Delphi method based on an iterative approach was used to obtain the final consensus data.

These examples show that the Delphi method is used in setting standards, forecasting the future, prioritizing, building indicators, and analyzing complex issues. This reflects the flexibility of the methodology and its ability to transform diverse expert opinions into a collective vision that can be relied upon in scientific research and decision making.

Conclusion:

In conclusion of this article, it becomes clear that the Delphi method represents an effective qualitative methodology that helps researchers reach a well-studied scientific consensus by leveraging the expertise of a group of specialists. This method has proven its ability to provide accurate insights into complex issues, thanks to its iterative steps that reduce bias and enhance the objectivity of results.

Delphi also provides a suitable methodological framework for future studies, priority setting, and knowledge-based policy-making. Thus, its use in scientific research is a sound methodological choice that improves the quality of results and provides researchers with a reliable tool for making more balanced and in-depth decisions.

Article References:

Al-Hadith, N., and Al-Obeid, I. (2021).Perceptions of education experts on the requirements for activating future studies in educational research: A study using the Delphi method.Arab Journal of Educational and Psychological Sciences, 5(23), 383-422.

Al-Turayqi, F. (2023).Future forecasting for green human resource management in intermediate government schools in Riyadh using the Delphi method.Journal of Educational and Psychological Sciences, 7(31), 77-100.

Al-Saeedi, A. (2025).Future forecasting of challenges for implementing artificial intelligence in guidance programs using the Delphi method.Arab Journal of Measurement and Evaluation, 6(11), 189-222.

Thwaites, L., Nasa, P., Abbenbroek, B., Dat, V. Q., Finfer, S., Kwizera, A., … & Myatra, S. N. (2025).Management of adult sepsis in resource-limited settings: global expert consensus statements using a Delphi method.Intensive Care Medicine, 51(1), 21-38.

Frequently Asked Questions(faqs)

What is the difference between the Delphi method and traditional methods for collecting opinions?

The Delphi method uses multiple rounds and organized feedback to reach consensus, while traditional methods like surveys or interviews rely on collecting opinions once without interaction among participants.

Should the experts’ identities be known to each other?

No, maintaining participant anonymity is a fundamental principle in Delphi, which reduces bias and mutual influence among individuals.

What is the ideal number of rounds in applying the Delphi method?

It typically ranges from two to three rounds, but can be increased or decreased depending on the nature of the subject and the degree of variation in opinions.

Can the Delphi method be implemented entirely online?

Yes, in fact, electronic implementation is one of the key strengths of this method, as tools like Google Forms or specialized platforms can be used to facilitate the process remotely.

How reliable are the results of the Delphi method?

The reliability of results depends on the quality of expert selection, question formulation, and the number of rounds. When properly implemented, its results are considered reliable and are used in public policies and strategic studies.