Understanding the Delphi Method and Its Applications

The Delphi method is a structured expert consensus technique widely used in strategic foresight to explore uncertain futures. When historical data is limited or emerging technologies and markets are changing rapidly, organisations can use the Delphi method to gather informed expert judgement and build a more robust view of future developments.

While trend analysis identifies emerging change and scenario planning explores multiple plausible futures, the Delphi method helps organisations systematically evaluate uncertainty through multiple rounds of expert input, building consensus while reducing the influence of individual bias

New to strategic foresight? Read our Strategic Foresight Practical Guide to learn how the Delphi method fits alongside other foresight frameworks, methods, and AI-powered approaches before diving into this article.

In this article, we’ll explain how the Delphi method works, when to use it, and how it supports strategic foresight and long-term decision-making.

What is the Delphi method?

The Delphi method is a structured research and decision-making technique that gathers input from a panel of experts through multiple rounds of questionnaires. After each round, participants receive an anonymous summary of the group’s responses and can revise their own answers based on the collective feedback. This iterative process helps build informed consensus while reducing the influence of dominant personalities, groupthink, and organisational hierarchy.

Unlike traditional workshops or brainstorming sessions, Delphi participants do not meet face to face. Responses are collected independently and anonymously, allowing experts to evaluate evidence and reconsider their views without pressure from others.

Developed by the RAND Corporation in the 1950s, the Delphi method was originally designed to support long-term military planning. Today, it is widely used across business, healthcare, government, and strategic foresight to evaluate complex questions where uncertainty is high and reliable historical data is limited.

How does the Delphi method work?

The Delphi method follows a structured, iterative process designed to gather expert judgement, reduce bias, and build consensus. While individual studies may vary, most Delphi projects follow these core steps.

1. Define research objective

Begin by clearly defining the problem, opportunity, or future uncertainty you want to explore. Establish a focused research objective and develop the key questions needed to gather expert insights. The Delphi method is most effective for complex issues where historical data is limited and expert judgement is needed.

For example, organisations might use the Delphi method to explore how AI could reshape their industry over the next five years, identify emerging market risks, or prioritise future R&D investments.

2. Select a panel of experts

Recruit a diverse group of participants with relevant expertise. Bringing together different perspectives helps organisations develop a more balanced understanding of complex issues while avoiding narrow or one-sided conclusions.

When selecting a panel, consider these best practices:

• Include expertise from multiple perspectives. Depending on the research objective, participants may come from both inside and outside the organisation. Combining different types of expertise helps create a more balanced and comprehensive view of complex issues.
• Choose participants with relevant expertise. Select individuals with direct knowledge or experience of the topic being studied. Establish clear selection criteria to ensure the panel has the expertise needed to address the research objective.
• Seek diverse viewpoints. A mix of backgrounds, disciplines, and experiences helps challenge assumptions, reduce blind spots, and improve the quality of the discussion.
• Balance expertise with practicality. The ideal panel size depends on the study’s objectives and available expertise. Business Delphi studies often involve 10–30 experts, while larger policy and public-sector studies may include up to 50 participants or more.
• Secure participants’ commitment. Because Delphi studies involve multiple rounds of questionnaires, participants should understand the purpose, expected time commitment, and timeline before agreeing to take part.

A well-designed expert panel is fundamental to the success of a Delphi study. The quality of the results depends not only on participants’ expertise, but also on the diversity of perspectives they bring.

3. Gather anonymous responses

Once the expert panel has been assembled, participants independently complete the first round of questionnaires. Responses are submitted anonymously, allowing experts to share their opinions, forecasts, or recommendations without being influenced by hierarchy, dominant personalities, or groupthink.

The first round often combines open-ended questions with structured rating or ranking exercises to capture both qualitative insights and quantitative assessments. For example, a study exploring the future of healthcare might ask experts which emerging technologies are likely to have the greatest impact on patient care before asking them to rank those technologies by expected impact.

The first round is typically exploratory, gathering a broad range of perspectives and ideas. As the study progresses, later rounds become more focused, allowing participants to review anonymous feedback, refine their responses, and move towards informed consensus.

4. Provide controlled feedback

After each round, responses are analysed and synthesised into an anonymous summary highlighting key themes, areas of agreement and disagreement, and the reasoning behind different viewpoints. Rather than sharing individual responses, participants receive a controlled summary that presents the group’s collective insights while preserving anonymity.

This controlled feedback allows experts to review the evidence, challenge their assumptions, and reconsider their own responses before the next round of questionnaires. By focusing on ideas rather than individuals, the Delphi method encourages informed reflection while reducing the influence of hierarchy, dominant personalities, and groupthink.

Today, AI can help streamline this stage by analysing large volumes of qualitative responses, identifying recurring themes, and generating draft summaries for facilitators to review. Human oversight remains essential to ensure feedback is accurate, balanced, and faithfully represents the full range of expert opinions.

5. Repeat additional rounds

The Delphi method typically involves two to four rounds of questionnaires. Each round builds on the previous one, allowing experts to review anonymous feedback, refine their responses, and progressively narrow areas of disagreement. The process continues until responses begin to stabilise, sufficient consensus has been reached, or the study has generated enough insight to answer the research objective.

6. Analyze the findings

Once the study is complete, the final responses are analysed to identify key insights, emerging patterns, areas of agreement, and continued uncertainty. Together, these findings help organisations understand where expert opinion is aligned, where important differences remain, and what they mean for future decision-making.

The findings are then synthesised into practical outputs such as reports, strategic recommendations, technology roadmaps, risk assessments, forecasts, or future scenarios. Depending on the objectives of the study, participants may also receive a summary of the final findings.

Rather than simply identifying consensus, a Delphi study helps organisations make better-informed decisions by combining expert judgement with a structured, transparent evaluation of uncertainty.

What makes the Delphi method effective?

The Delphi method is built on four key principles:

• Anonymity reduces the influence of hierarchy, dominant personalities, and groupthink.
• Controlled feedback allows participants to learn from the group’s collective insights while remaining independent.
• Iteration gives experts the opportunity to refine their views as new information emerges.
• Diverse expertise brings together different perspectives to produce more balanced, well-informed outcomes.

Who typically participates in a Delphi study?

Unlike traditional workshops, Delphi panels often combine expertise from multiple organisations and disciplines. Depending on the research objective, participants may include internal subject matter experts alongside external specialists who bring complementary knowledge and independent perspectives. Depending on the research objective, a Delphi panel may include:

• Internal experts, such as strategy, product, engineering, or R&D leaders.
• Academic researchers, who contribute subject-matter expertise and independent perspectives.
• Industry practitioners and consultants, who bring practical experience and market knowledge.
• Customers, suppliers, or partners, who provide insights from across the value chain.
• Government or policy experts, particularly for studies involving regulation, public policy, or long-term societal trends.

What are the benefits and limitations of the Delphi method?

Benefits	Limitations
Reduces groupthink through anonymous participation	Requires multiple rounds, making it more time-intensive than surveys or workshops
Brings together diverse expert perspectives	Results depend on selecting the right experts
Encourages informed reflection through controlled feedback	Questionnaire design and facilitation have a significant impact on quality
Well suited to complex problems where historical data is limited	Does not predict the future with certainty
Creates a structured and transparent decision-making process	Reaching consensus may not always be possible or desirable

When should you use the Delphi method in strategic foresight?

The Delphi method is particularly valuable when you need to:

• Explore long-term uncertainty where historical data is limited.
• Gather structured expert judgement from multiple disciplines.
• Develop future scenarios or technology roadmaps.
• Prioritise emerging risks and opportunities.
• Inform strategic planning with a transparent, repeatable process.

Consider another approach if:

• Reliable quantitative data already answers the question.
• You need a rapid operational decision.
• A survey, interview, or workshop would provide sufficient insight.
• The objective is to validate existing evidence rather than explore future uncertainty.

The Delphi method: turning expert judgement into better decisions

The Delphi method provides a structured way to gather expert judgement, explore uncertainty, and support better long-term decisions. While it is just one strategic foresight technique, it’s particularly valuable when historical data is limited and organisations need informed perspectives on the future.

Learn how the Delphi method fits alongside other foresight approaches in our Strategic Foresight Practical Guide.

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