Online Delphi Technique — e-Delphi
Online Delphi Technique (e-Delphi) · Also known as: e-Delphi, electronic Delphi, web-based Delphi, internet Delphi
The Online Delphi Technique (e-Delphi) is an iterative, web-mediated consensus method in which a geographically dispersed panel of experts responds to successive rounds of structured questionnaires distributed and collected via email or a web platform. Anonymous feedback and controlled statistical summaries are fed back between rounds, guiding panellists toward convergence on priorities, predictions, or recommendations without the social pressures of face-to-face group discussion.
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When to use it
Use the Online Delphi Technique when you need structured expert consensus on a topic where empirical data are scarce, where established evidence is contested, or where prediction and priority-setting are the goal — for example, identifying future research priorities, developing clinical guidelines, or validating competency frameworks. The online format is especially advantageous when experts are geographically dispersed, when real-time meeting is impractical, or when asynchronous participation is required. Do not use it when the goal is exploratory qualitative understanding (use interviews or focus groups instead), when a single-round survey suffices (no iteration needed), when the panel cannot be identified because 'expertise' is diffuse, or when the research requires statistically representative population data rather than expert opinion.
Strengths & limitations
- Eliminates geographic and scheduling barriers, enabling truly international or multidisciplinary expert panels.
- Asynchronous participation gives panellists time for considered, reflective responses rather than reactive group-dynamic answers.
- Anonymity reduces conformity pressure and allows minority expert views to be expressed and tracked across rounds.
- Iterative feedback with statistical summaries drives genuine convergence while preserving transparent documentation of dissent.
- Lower cost and faster turnaround compared to in-person Delphi, particularly for large or widely distributed panels.
- Requires panellists to have reliable internet access and sufficient digital literacy to navigate online survey platforms.
- Response attrition across rounds is a persistent threat; dropout between round one and later rounds can bias the consensus toward the views of the most motivated or available respondents.
- Consensus does not equal correctness — the method surfaces shared expert opinion, not empirical truth, and can be skewed by the composition of the panel.
- Designing valid, unambiguous questionnaire items demands significant methodological skill; poorly worded items produce spurious consensus.
- The anonymised aggregation sacrifices the richness of interpersonal dialogue that face-to-face deliberation can generate.
Frequently asked
How many rounds does an Online Delphi require?
Most Online Delphi studies use two or three rounds. The first round generates or rates items; the second provides group feedback and asks for revised ratings. A third round is added only if consensus has not been reached. Beyond three rounds, attrition and fatigue typically outweigh the marginal gain in convergence.
How is consensus defined?
There is no single universal criterion. The most common approach is an interquartile range of 2 or less on a 9-point scale, indicating that the central 50% of panellists are within a 2-point band. Some studies use a percentage-agreement rule (e.g., 70% or 80% of panellists rating an item in the same directional band). The key requirement is that the criterion is pre-specified in the study protocol.
What is the difference between an Online Delphi and an online survey?
An online survey is a single-round data collection instrument with no feedback or iteration. The defining feature of the Delphi — online or otherwise — is the iterative loop: panellists see anonymised group statistics after each round and have the opportunity to revise their ratings in light of that feedback. Without iteration and feedback, the instrument is a survey, not a Delphi.
How many experts should be on the panel?
There is no consensus on a minimum, but panels of 10–50 are typical. Fewer than 10 risks insufficient diversity of expert opinion; more than 50 creates substantial administrative burden and may slow the study. Panel size should be driven by the diversity of expertise required rather than a statistical power calculation, since the Delphi is not designed for inferential statistics.
Can I use a free survey tool like Google Forms for an e-Delphi?
Yes, with caveats. Google Forms or similar tools can collect responses and export data for analysis, but they do not automatically generate the statistical feedback summaries (medians, IQRs) needed between rounds. The researcher must compute and format these summaries manually before distributing the next round. Dedicated Delphi platforms such as DelphiFlow or ExpertLens automate this workflow but require licensing.
Sources
- Hasson, F., Keeney, S., & McKenna, H. (2000). Research guidelines for the Delphi survey technique. Journal of Advanced Nursing, 32(4), 1008–1015. DOI: 10.1046/j.1365-2648.2000.01567.x ↗
- Donohoe, H., Stellefson, M., & Tennant, B. (2012). Advantages and limitations of the e-Delphi technique: Implications for health education researchers. American Journal of Health Education, 43(1), 38–46. DOI: 10.1080/19325037.2012.10599216 ↗
How to cite this page
ScholarGate. (2026, June 3). Online Delphi Technique (e-Delphi). ScholarGate. https://scholargate.app/en/survey-methodology/online-delphi-technique
Which method?
Set this method beside its closest kin and read them side by side — the library lays the books on the table; the choice is yours.
- Delphi TechniqueSurvey Methodology↔ compare
- Nominal Group TechniqueQualitative↔ compare
- Online Focus GroupSurvey Methodology↔ compare
- Online Structured InterviewSurvey Methodology↔ compare
- Online SurveySurvey Methodology↔ compare