Comparing Delphi and NGT Decision Techniques

Two of the most popular tools for evaluating and prioritizing ideas are the Delphi Technique and the Nominal Group Technique (NGT). But, do enough research on decision-making strategies and they all start to blur together. Let’s take a closer look at how each technique works, and when they’re best used.

The Delphi Technique vs Nominal Group Technique

The Delphi Technique

The Delphi Technique relies on questionnaires to gather information and insights from a panel of experts who remain anonymous to decision-makers for the purposes of candor.

The questionnaires are delivered in rounds. The questions in each round are determined by the responses from the round before and are accompanied by the decision-makers participant-specific questions or requests for clarification. Members of the expert panel are encouraged to provide additional feedback or commentary on their own responses as well as the responses of other panelists.

Starting in the second round, panelists are asked to rank the ideas presented by order of priority. They are asked to defend their prioritization in relation to other panelists’ decisions in later rounds. The questions grow progressively more focused on a small subset of ideas on which the board may reach a consensus.

Read our full article on the Delphi Technique here.

Nominal Group Technique

Nominal Group Technique relies on a moderator who records the ideas produced during an individual brainstorming session. Group members read their ideas aloud to the moderator. Each idea is discussed solely for the purposes of gathering information rather than debate.

Decision-makers then vote using index cards numbered one through five. The numbers correspond to the priority the idea (which must also be written on the card) should receive. A score of “five” indicates an idea should receive the highest priority while a score of “one” indicates a voter’s lowest priority. The votes are then tallied. The ideas are pursued in order of the priority score they received (from highest to lowest).

Read our full article on the Nominal Group Technique here.

When to Use Each Technique

While both techniques rely on a system of “rounds” — the questionnaires in the Delphi Technique and the discussion structure of NGT — they differ in the source of information and insights. While both require the use of a moderator, the responsibilities of Delphi moderators are far greater and more demanding than those placed on the NGT moderators.

While each method, may appear similar at first glance, the situations in which they’re employed are vastly different. Nominal Group Technique is often used to inform less consequential decisions. It can be performed quickly and relies on the knowledge of participants without the time to conduct any further research. Because of this, NGT is often used to make the small- to-medium sized decisions which require some discussion without the need for additional or third-party opinions.

On the other hand, The Delphi technique may require weeks of going back and forth between panelists and decision-makers. This provides participants with the time to ensure the information they submit is well-informed. When performed effectively, the Delphi Technique should lead the selection of ideas which best meet the needs of decision-makers. This makes it perfect for addressing high-stakes issues which require a thorough examination of options and leveraging of expertise.

While learning the finer details of each decision-making technique isn’t easy, gaining a basic understanding of how they work and when they’re best used is a piece of cake. We hope this gives you enough of an understanding to decide between the two when the time comes!

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