01 · Purpose and selection
Purpose and selection
Nominal Group Technique is a structured group process that separates generating ideas from discussing and ranking them. Participants first think independently, then contribute in turn, clarify the collected ideas, and prioritize privately. Its purpose is to reduce domination by a few speakers and expose ideas that might disappear in an ordinary open discussion. It is especially useful when different roles have practical knowledge but unequal confidence or authority.
Use it for a bounded question where the team needs a set of proposals or relative priorities. It is not a process for proving a cause or replacing specialist approval. Prerequisites include a neutral facilitator, a clear question, enough time for silent thinking, and a group small enough that every person can contribute. If essential information is missing, clarify that information first. Otherwise the structure merely produces a polished ranking of misunderstandings.
02 · Prepare a question that invites useful answers
Prepare a question that invites useful answers
Fictional Northbank Dispatch invites six people: a picker, a dispatcher, a night-shift lead, a transport coordinator, a systems analyst, and a quality representative. The question is “Which changes could prevent cartons reaching staging without a usable carrier assignment?” It is narrower than “How can we improve the warehouse?” and broad enough to admit process, information, and layout ideas.
The facilitator supplies the observed sequence and a few verified examples, while avoiding a preferred solution in the introduction. Each participant writes ideas silently for ten minutes. The time is a local facilitation choice, not a required duration. Silence protects independent thinking from early anchoring. Participants may write several ideas, but each statement describes one proposed change. The facilitator explicitly welcomes contrary suggestions and explains that a later ranking will choose candidates for investigation rather than authorize spending.
03 · Round-robin capture and clarification
Round-robin capture and clarification
Each person offers one idea per turn until the group has exhausted its list. A person may pass and return on a later round. The facilitator records the wording visibly without debating its merits. The process preserves participation without requiring everybody to speak at length. Similar ideas remain separate until participants agree that combining them would not erase an important difference.
Clarification follows capture. Northbank distinguishes “assign the carrier earlier” from “show the assignment earlier”: one changes the timing of the decision, while the other changes access to information. It also distinguishes preventing a label failure from making reprinting faster. Participants explain assumptions and operational implications, but advocacy is kept brief. The rationale is to make proposals comparable before the ranking. People should not vote for a phrase that means one thing to systems staff and another to the night shift.
04 · Worked ranking with explicit local rules
Worked ranking with explicit local rules
The group reduces its list to seven distinct concepts. For this session, each person privately ranks three preferred ideas, assigning three points to first, two to second, and one to third. This six-point allowance produces thirty-six possible points across six participants. The rule is declared before ballots are completed; it is a local ranking design rather than a universal NGT scoring requirement.
Totals are early assignment fourteen, scan confirmation nine, night-shift display six, standard reprint handling four, lane markings two, printer relocation one, and reminders zero. The sum is thirty-six. Early assignment leads the preference ranking, but fourteen points do not measure its operational benefit. The group examines why the night-shift display received six points: night staff lack access to a board used on days. That finding becomes a design condition for the early-assignment concept rather than a separate competing project.
05 · Convert agreement into a next decision
Convert agreement into a next decision
The team selects early assignment and scan confirmation for feasibility assessment, with night-shift access included in their design. It retains the reprint proposal as a separate issue because it addresses a different delay mechanism. The quality representative records a concern that scan confirmation could fail during a network interruption. That concern becomes a must criterion and recovery requirement, even though the fallback itself was not the highest-ranked idea.
The facilitator publishes the question, participant roles, combined list, ranking rule, tally, and next action. This creates a traceable boundary between group preference and management authorization. Before committing resources, the team checks cost, traceability, layout, and testability. NGT has produced balanced input and a defensible shortlist, not consensus that the leading option is proven. A participant who remains unconvinced can see how the objection will be tested rather than being pressured to endorse the score.
06 · Limitations and advanced use
Limitations and advanced use
Weak practice allows a manager to explain a preferred answer before silent writing, debates each idea during capture, or treats a point total as a benefit forecast. Another weakness is forced consensus, where a minority concern is erased because the ballot has already selected a winner. Strong practice protects independent input, clarifies meanings, preserves dissent, and gives the ranking a limited decision role.
Advanced teams use separate sessions for distant sites or shifts, then compare the mechanisms proposed before creating a combined list. This avoids a large group in which people stop contributing. They may also ask participants to record confidence and information gaps separately from preference. An idea with high preference but weak evidence deserves an investigation, while an idea with lower preference but a severe risk implication deserves a control review. The disciplined separation of generation, clarification, ranking, and evidence is what makes NGT useful.
07 · Operating conditions and evidence
Operating conditions and evidence
Facilitation includes access, not just turn-taking. Northbank provides the process sequence in plain language and allows participants to write before speaking. A systems acronym is explained before the ranking. If a person cannot attend the session, their observations can inform the preparation, but their absence should not be hidden by calling the result representative of every shift. The participation record states which roles and conditions were covered.
The facilitator also checks whether clarification has turned into persuasion. A statement such as “this will definitely save two people” is challenged for evidence rather than allowed to dominate the ballot. Participants can state a predicted effect and the assumptions behind it. If an issue needs data, it becomes an investigation item. The structured meeting remains effective because it separates what the group knows, what it proposes, and what it prefers. Those distinctions make the final shortlist usable by a project owner who was not present.
08 · Decision record and next step
Decision record and next step
A good NGT record retains the distinction between an idea and the supporting argument. Northbank’s early-assignment proposal is one concept; the claimed reduction in searching is a hypothesis supporting it. If the hypothesis fails in a pilot, the team can reconsider the concept without rewriting the meeting record. This discipline is particularly useful when a proposal later becomes a detailed systems requirement and the original rationale risks being forgotten.
The group also agrees how the result will be communicated to absent staff. The facilitator shares the clarified concepts, the ranking convention, and the planned evidence review. It does not announce that “everyone agreed” when only six roles participated and some concerns remain. Accurate communication supports later adoption because operators can see how their conditions were considered. Structured participation produces useful judgment when the organization preserves both the leading ideas and the unresolved questions that accompany them.
| Stage | Required behavior | Evidence retained |
|---|---|---|
| Silent generation | Protect individual thinking before advocacy | Original ideas and the bounded question |
| Clarification | Resolve meaning without forcing agreement | Combined concepts and unresolved assumptions |
| Ranking | Use private ballots under declared rules | Thirty-six points checked against the ballot allowance |
Connections
Related methods and phase use
Placed under Improve because of the outcome it supports. Use the method in other phases when its purpose and assumptions fit the work; the phase list is a guide to selection, not a compulsory sequence.
Sources
Professional foundations and further reading
The explanation and fictional teaching examples are written for LeanTrainingLab. Linked primary sources provide professional foundations; example values and local conventions are stated in the guide. The accepted toolset draws on Six Sigma+Lean Toolset, second edition (Lunau, editor; Springer, 2013). No book text or examples are reproduced here.