Email   Print
Resource Center > Process Improvement Toolbox > How to Use the Nominal Group Technique

Nominal Group Technique

The Nominal Group Technique (NGT) is designed to promote group participation in the decision-making process

The Nominal Group Technique can be used by small groups to reach consensus on the identification of key problems or in the development of solutions that can be tested using rapid-change cycles.

Within NIATx, a modified version of the NGT was used to solicit ideas that form the basis of the Promising Practices.

Frequently asked questions about the NGT


STEP 1: Preparation

Prior to using the Nominal Group Process, it is necessary for the meeting facilitator to complete a set of sequential preparatory tasks that set the stage for a successful meeting:

  • Design preparation
    • Prepare the NGT question that clarifies the objective of the meeting and illustrates the desired responses in terms the level of abstraction and scope. Often the leader will pilot test the question prior to the meeting.
    • Print the question on worksheets for each participant.
    • Select the desired voting method (e.g., ranking vs. rating).
  • Room preparation
    • Secure a room large enough to comfortably seat group participants (five to nine persons) at individual U-shaped tables. Note: if the NGT process involves a large number of persons, please provide adequate separation between the tables for each group.
    • Bring the following supplies: flip charts, masking tape, markers, pens and paper for each participant and either 3" x 5" index cards or post-it notes.
  • Meeting preparation
    • Prepare a welcome statement that explains the purpose of the meeting, outlines individual roles, and describes how the output will be used.
    • Conduct the meeting following the NGT process.

[Back to top]

STEP 2: Silent idea generation

Prior to starting, the group leader should prepare and present, in writing and verbally, the question that the group will consider during their meeting. A well-thought-out question will help generate a wealth of potential ideas. The leader will encourage participants to silently and independently write ideas in brief phrases.

The benefits of silent generation include:

  • Allows adequate time for thinking and reflection through recall
  • Promotes social facilitation (e.g., seeing others hard at work)
  • Avoids interruptions, undue focus on one idea, and competition, as well as status and conformance pressures or choosing prematurely between ideas
  • Promotes a problem-centered focus

Back to top

STEP 3: Round-robin recording of ideas

In this step, the group leader goes around the table and records one idea from each participant on the flip chart. The ideas should be recorded verbatim with little to no paraphrasing by the leader. However, leaders are allowed to ask questions for clarification of the idea. The process continues until all ideas have been recorded. When a participant is out of ideas, they should indicate by passing.

The benefits of the round-robin recording are that it:

  • Promotes equal participation in the presentation of ideas
  • Increases problem-mindedness and the ability to deal with a large number of ideas
  • Separates the ideas from the person
  • Allows for the tolerance of conflicting ideas
  • Encourages hitchhiking on ideas
  • Provides written records of the ideas

In the NGT process, hitchhiking refers to a process that may stimulate other participants to think of an idea not recorded during silent generation and allows them to record and offer it during their turn.

Back to top

STEP 4: Serial discussion of ideas

This involves taking each idea, one at a time (serially) and discussing or clarifying the idea prior to the preliminary vote. The benefits of this step are that it:

  • Avoids unduly focusing on any one idea or a subset of ideas
  • Provides an opportunity for clarification and the elimination of any misunderstanding
  • Outlines the arguments and disagreements over ideas
  • Records differences of opinion without undue augmentation

Back to top

STEP 5: Preliminary voting

During this stage, the group participants will begin to narrow the list of potential ideas. Building on the discussion of ideas, each member will make an independent judgment about those ideas that they consider most likely to represent the problem to be solved or the potential solution to address it.

The two voting methods, typically used, are ranking and rating.

Rating method: When rating the ideas, each participant distributes a set number of points (e.g., 100) across the ideas, as seen in the example table below:

Rating Method
Idea # Joe Sue Kelly Jim Total
1 50 50
2 40 30 70
3 20 100 32 152
4 0
5 30 30
6 20 30 50
7 0
8 0
9 20 5 18 43
10 5 5
Total 100 100 100 100 400

As seen in the table above, each of the four team members distributed their points across the ten ideas they generated during Step 2 . Note that participants have the option of assigning all of their points to one idea if they feel strongly that it is truly the best (i.e., Sue). From the table, it can be seen that Idea 3 has the highest point total, and the team can end the NGT process at this point, and choose this option.

In another variation of this method, participants assign colored dots to ideas, using the same process.

Ranking method: When ranking items, each participant is asked to choose roughly half of the total number of ideas generated, and to rank these from most important to least important. This process will place emphasis on fewer ideas. In preparation for recording the vote, the leader should list the number of each idea on a separate piece of paper. When the actual votes are recorded, she/he will record the rank assigned by each participant to the idea, as seen in the example below.

Ranking Method
Idea # Joe Sue Kelly Jim Total
1 1 5 6
2 5 5 10
3 4 5 4 13
4 0
5 3 4 1 8
6 2 4 3 2 11
7 0
8 2 2
9 3 1 2 3 9
10 1 1

As seen from the table above, Idea 3 has the highest score. In many instances, the NGT process will end after this step. If greater accuracy is desired, and especially if the group has generated a large number of ideas, the group may chose to engage in the following two additional steps ( Step 6 and 7 ), and iterate as many times as needed.

Back to top

STEP 6: Discussion of preliminary voting

This brief step in the NGT process is designed to examine items with inconsistent voting patterns and provide an opportunity for a discussion of ideas perceived as receiving too many or too few votes. While this step seldom results in radical changes in how the groups perceives an idea, it can result in a more accurate final vote.

Back to top

STEP 7: Final voting

In this final step, individual judgments on the ideas are combined into a group decision. While the leader may chose to follow the same voting technique used in Step 5 , they also may choose to use a more refined voting technique such as rating.

The final vote helps:

  • Determine the outcome of the meeting
  • Provides a sense of closure and accomplishment
  • Records the final group judgment in relation the initial question

Back to top

FAQs about the Nominal Group Technique

Q: How many people can participate in an NGT group?

A: The ideal size of the group is five to nine persons. A group of this size provides different perspectives and critical judgment to analyze the problem and arrive a decision to address it. A smaller group does not ensure adequate participation in the decision process and while a larger group will generate more ideas, it will take too long to list, discuss, and vote on them.

Q: How can I use NGT with larger groups?

A: Divide the group into equal sub-groups. Each sub-group will complete steps 1 to 4 separately. During a pre-arranged 1 ½ hour lunch, the top 5 ideas from each sub-group are recorded, combining any duplicate ideas, and a master list of ideas is generated. The larger group then meets for discussion and a final vote on the top ideas.

Q: Should you eliminate duplicate items prior to preliminary voting?

A: When NGT is used for problem identification, idea elimination is not recommended. However, it is sometimes desirable to combine ideas if NGT is used for priority setting.

Q: When should ideas be combined or eliminated?

A: The process should take place after discussion but before preliminary voting.

Q: How should ideas be combined or eliminated?

A: Two approaches exist. First combine all ideas into a single factor. Second, the group would add a factor title but maintain the individual items that comprise the factor. For example, the factor might be "Reduce internal paperwork requirements" while the individual items might include (a) review forms—eliminate duplicate questions and discard no-longer-needed forms, (b) reduce number of questions and forms by asking the question "What is this information used for? How does it increase quality of access or retention?" or conducting a cost-benefit analysis and (c) combine all legal documents into one form and use a general waiver signature.

Note: During voting, the group would vote on the individual items not the combined factor.

Back to top

Q: What is the difference between rating versus ranking as a voting method?

A: Several factors guide the process. First, the number of ideas. Ranking is easier with smaller lists, while rating works with larger lists as it reduces individual decisions regarding how to rate the ideas generated. Second, accuracy. Rating provides greater indication of individual preferences. Finally, gaming. Rating ideas provides an individual with the opportunity to drive idea selection towards their preference.

Q: How does rating work?

A: Assume that NGT generates ten ideas. Then individuals would rate their preference in order of most important (10) to least important (1). The scores across all individuals would be summarized to provide the final group preference for the ideas generated.

Q: How does ranking work?

A: Using the same ten ideas, the individual would be given 100 points to distribute across all ten ideas. In this instance, they can assign a larger portion of the points (e.g., 50) to one idea and then distribute the remaining 50 points across the other nine ideas. In essence they rank more highly the idea that they prefer the best.

Another variant of ranking is to provide the individuals with sticky dots equal to about half of the number of ideas generated and allow them to distribute the dots across multiple ideas or assign all of their dots to one idea.

Regardless of the approach, the final tally for each idea is determined by calculating the total ranking or dots assigned to each idea.

Q: How do you write a good NGT question?

A: A properly written question will help stimulate idea generation and is an important initial step. The recommended process involves: (a) staff discussion of the meeting objective, (b) a determination of the types of responses desired (e.g., depth and breadth), and (c) developing and pilot testing alternative questions with a sample group. Ultimately, good question writing comes from hard work and trial and error learning.

Q: How can I ensure that others will adapt the decisions reached at the NGT meeting in the organization?

A: You cannot. While group acceptance will be high, others in the organization will judge the ideas on acceptability and quality.

Back to top

Q: Will more extroverted individuals still dominate the meeting, especially during discussions?

A: While these individuals may speak more during idea discussion, independent voting still allows individual input by group members into the selection of the final ideas.

Q: Who should be invited to participate in a NGT meeting?

A: Group members should have interest in and experience with the problem and be open minded enough to explore different points of view.

Q: What skills should the leader possess to overcome resistance to an unfamiliar technique?

A: She/he should understand the process; be self-confident enough to lead the group through the process and be accepted by peers in order to lead the group effectively.

Q: What are the advantages of the NGT?

A: It is useful when the decision-making process is complex and requires the pooling together of ideas from different individuals. Specifically, NGT helps identify the elements and potential solutions of a problem, and then allows group members to prioritize those solutions.

Q: When should the NGT not be utilized?

A: Time: it takes about 60 to 90 minutes to complete. Space: the physical layout of a room to support NGT may not be present. Focus: NGT deals only with one question or issue.

Back to top

SOURCE: This tool is based on information derived from reading Group Techniques for Program Planning: A Guide to Nominal Group and Delphi Processes by Andre L. Delbecq, Andrew Van de Ven and David H. Gustafson, Scott, Foreman and Company, Glenview, Illinois, 1975