Top 5 techniques for group decision making in Six Sigma

techniques for group decision making

Decision-making in a group or team is not easy and that’s why as a team leader you need to use some effective group decision-making techniques. These techniques offer you and your team a step-by-step structure when it comes to making a quality decision and finding a solution to the problem.

While working on a Six Sigma project or any improvement project it is very important that the project team should make fast and quality decisions in order to get a successful outcome at the end of a project.

But due to the different opinions and perspectives of each team member, it becomes difficult for the project team to make quality decisions. To overcome this difficulty group decision-making techniques are useful.

In this process, multiple individuals come together and analyze the problems from different angles, evaluate different ways to solve that problem and select the right solution at the end.

In this article, I am going to share with you the 5 important group decision-making tools or techniques that can help you make quality decisions easily with the consensus of all your team/group members.

In the end, you will understand the application of all 5 techniques and the step-by-step procedure to use these 5 techniques for effective decision-making. So let’s start…


5 techniques for group decision making in Six Sigma –

While working on an improvement project, the stage comes where all the team members come together to generate new ideas and insights to solve the problem at hand. (It can be anything like improving the process, reducing variation, increasing the cycle time of the process, etc)

In such situations, there is a high chance that the project team may face obstacles in making effective decisions or selecting the right ideas to solve problems due to the different opinions/perspectives of team members.

Hence, soliciting ideas from all team members by providing an equal opportunity and arriving at a single conclusion requires the use of a systematic and proven approach.

So these 5 techniques for group decision-making are useful for guiding team/group interaction in a systematic way. Now let’s understand those techniques one by one – 


1. Brainstorming – 

Brainstorming is a group creativity technique by which efforts are made to find a conclusion for a specific problem by gathering a list of ideas spontaneously contributed by its members. This technique generates a large number of creative ideas in a short period of time.

It is used when a broad range of options and creative original ideas are required. The best thing about this group decision-making technique is it encourages team participation and involvement in the decision-making process.

Brainstorming combines s relaxed, informal approach to problem-solving with lateral thinking. It encourages people to come up with thoughts and ideas that can at first seem a bit crazy but in the long term so much useful.

Some of these ideas can be crafted into original, creative solutions to a problem, while others can spark even more ideas. This help to get people unstuck by jolting them out of their normal ways of thinking.

Careful attention should be paid to everyone’s nuances and information as you move through the brainstorming process. Ideas should be heard, captured, and entertained, they should not be judged or interrogated in terms of their practicality or implementation.

The focus of this technique is to capture all the possible great ideas and get them down on paper so that all the team members can work on those ideas. Here quantity of ideas is more important than quality. During this process, make sure that your team should avoid criticizing or rewarding ideas because that may limit creativity.

This one of the powerful group decision-making techniques is more geared toward generating ideas than coming to a final decision but sometimes one idea stands out from others and can be selected as the most effective idea or solution to the problem.

Now let’s see a simple procedure to perform brainstorming.

Brainstorming group decision making


Brainstorming procedure – 

  1. Review the problem definition.
  2. Clarify the goal/questions and provide any relevant information.
  3. Give everyone some time in which they can silently think about the question and individually write down some new ideas. (For writing ideas use self-stick notes or color cards)
  4. Gather as many ideas as possible – Use two methods in the 1st method team members state ideas one at a time and in the 2nd method any team member can state ideas at any time. So that everyone gets an equal opportunity to contribute. That’s how you should capture every idea stated by all the team members,
  5. Record all the ideas on a whiteboard or flip chart – Post all the ideas on the wall, board, or flip chart so that everyone in the team can see those ideas. Don’t allow any type of discussion until all the ideas are noted and continue this process until everyone is out of ideas. 
  6. Consolidate all the similar ideas and start discussing all sets of ideas under the guidance of the team leader. After that, to organize those ideas in a systematic way we have other tools and techniques.

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2. Nominal group technique (NGT) – 

This is again one of the best group decision-making techniques, where the structured meeting is held among the limited group members where they are required to find solutions to the problem identified for the discussion in a very systematic and organized way.

This technique is applied when some group members are much more vocal than others, and to encourage equal participation from all members.

This technique helps in preventing the discussion from being dominated by a single person and hence, allows the silent members, who are quite shy, to speak out their ideas in the group.

The name of the technique is the Nominal group technique which means the discussion is carried out in small groups, which helps alleviate peer pressure and reduces the impact of such pressure on the generation of creative ideas.

The objective of NGT is the same as brainstorming which resolves the opinion conflicts among the group members by enabling each individual to pen down his/her thoughts about the problem and later discuss it with the entire group to reach a consensus solution.

In this technique, no judgment or criticism is passed. The ideas are simply written down. The members are allowed to expand on existing ideas, provide clarity, and eliminate redundancy during consolidation.

Now let’s see a simple procedure to perform NGT.

Nominal group technique

Nominal group technique procedure – 

  1. State the subject of the NGT brainstorming. Clarify the topic properly until everyone understands it.
  2. Each team member will be given 10 to 15 min so that they can silently think of and writes down as many ideas as possible in a set period of time.
  3. Each group member in turn states aloud one idea, Facilitator records it on the flipchart. No verbal interaction is allowed during the session.
  4. All the ideas are collected and posted on a whiteboard or flipchart where all can easily read them.
  5. Discuss each idea in turn. This discussion may clarify the meaning of each idea, explain the logic behind it, and raise questions and answers, or state agreement/disagreement,
  6. Then go for prioritization of these ideas using tools like multi-voting and affinity diagrams.


3. Multivoting – 

Multi-voting is one of the best idea prioritization techniques used in group decision-making. It can be successfully used with both brainstorming and NGT results. Even though this tool is typically used in combination with NGT, it can be a technique on its own.

It is a technique for narrowing a wide range of ideas or choices down to the few most appropriate, feasible, and important. This basically saves time while still considering every idea that has been generated.

It is the method of conducting a vote with team members to select the most important or popular ideas from the list with limited discussion and difficulty. Use this technique to narrow down a list to a few high-priority items.

The multi-voting session requires a group of participants and a topic for discussion that will generate a list of ideas, issues, or problems. Its primary goal is to reduce the range of options thereby preventing “information overload.”

Multi-voting is also known as N/3 voting where N refers to the total number of ideas. Every team member is given N/3 votes and instructed to vote on the most important ideas, the team member can only assign one vote per idea.

For example – if there are 30 ideas, each team member gets 30/3 or 10 votes each. Since there are fewer votes than there are ideas, the less important ideas will naturally be weeded out, thereby reducing the number of ideas the team must contend with.


Multivoting procedure – 

  1. Display the list of ideas or options. Eliminate duplicates and combine related ideas before continuing. An affinity diagram can be useful to organize a large number of ideas and eliminate duplication.
  2. Number every idea or option being considered.
  3. Decide how many items must be on the final reduced list. Decide also how many choices each member will vote for. Usually. five choices are allowed. The longer the original list, the more votes will be allowed up to 10.
  4. Working individually, each member selects the five ideas/items he or she thinks are most important. Then each member ranks the choices in order of priority, with the first choice ranking highest. Eg- If each member has 5 votes, the top choice would be ranked five, the next choice four, and so on. (Each choice is written on separate paper with ranking underlined in the lower right corner.)
  5. Tally votes, collect the papers, shuffle them, and then record on a flipchart or whiteboard. The easiest way to record votes is for the scribe to write all the individual rankings next to each choice. (For each item, the rankings are totaled next to the individual rankings.)
  6. If the decision is clear, stop here. Otherwise, continue with a brief discussion of the vote. The purpose of the discussion is to look at dramatic voting differences, such as an idea or item that received both a 5 and 1 rating, and avoid errors from incorrect information.
  7. Make sure the discussion does not result in pressure on anyone to change their vote. Repeat the voting process and if high decision-making accuracy is required, this voting may be done by weighting the relative importance of each choice on a scale of 1 to 10. (1- least important, 10 – most important)


4. Affinity diagram – 

The affinity diagram is next one of the best idea organization techniques or tools in group decision-making. It is useful to organize data/ideas gathered from the brainstorming session in any phase of the DMAIC project and identify central themes in a set of ideas.

It is helpful to organize facts, opinions, and issues into natural groups to help diagnose a complex situation or find themes and messages in customer statements gleaned from interviews, surveys, or focus groups.

It simplifies analyzing complex data (in the form of ideas) by grouping them, which helps bring out connections among the different ideas.

The use of an affinity diagram is highly recommended when information about the problem is not well organized and when a breakthrough is needed beyond traditional thinking.

Affinity diagram for group decision making

Affinity diagram procedure – 

  1. Gather ideas from brainstorming sessions or customer need statements from interviews transcripts, research or surveys, etc.
  2. Write ideas on cards or self-stick notes (one idea per card stays as close to the original language as possible.)
  3. Post-self-stick notes randomly on a board or flip chart (if using cards place them randomly on the tabletop.)
  4. Allow all the team members to silently start grouping the cards or notes. Review all the ideas and start grouping them based on similarities until no cards are left.
  5. When the grouping of ideas is done then create a header label for each group. The header label should convey the relationship between ideas in a single word or phrase. (Remember that – work through group one at a time, ask participants to interpret what they see and also ask them to suggest a label or key theme for that group.)
  6. Make sure you have grouped all the idea cards properly and labeled them with the correct headings. Follow this step until all the idea cards are properly arranged in the group with the heading. Make sure the diagram looks visually attractive and easy to understand.
  7. Lastly, write down the problem statement on the top of the diagram and gather your project team, and start reviewing which idea to prioritize or select to solve the problem. After that, you can go with other process improvement tools to work on problem-solving.

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5. Criteria matrix diagram – 

The criteria matrix is one of the valuable group decision-making techniques used to assess and rank a list of options based on specific criteria. Eg – a criteria matrix can be used to compare the advantage and disadvantages of two options, choices, or alternatives.

It is a technique designed to prioritize a group of potential alternatives under consideration. This is accomplished by identifying and weighing agreed-upon criteria against each of those alternatives.

Establishing criteria forces a group to articulate and examine their values, rationales, and assumptions before making their decision. Criteria are standards from which one makes judgments or decisions and their identification becomes the basis for evaluation. 

Eg- If your project team wants to purchase a specific piece of equipment for the project and your team has a maximum of $35000 to spend, this amount is the criteria for the final decision.

Any equipment over that amount does not meet your criteria and therefore your team would not likely choose it. That means once all the criteria for the equipment you want to purchase are identified and agreed upon, your project team can investigate the alternative more objectively.

It is much easier to reach a consensus when making a decision if the criteria are identified and agreed upon beforehand. Team members are much more willing to give up their favorite choices or ideas when they see that these favorites don’t meet the necessary criteria.

If there is no agreement on the criteria upfront, it is less likely that there will be agreement on the best alternative when it comes time to make the decision.

This is one of the best group decision-making techniques because it is based on standard criteria and those criteria help to prevent conflict among team members regarding different choices and opinions.

This tool makes it easy for the team to make effective decisions with complete consensus. This technique is useful when a decision has many components or criteria which must be factored in.

It is useful when different opinions and perspectives of team members must be considered. This tool is highly recommended when it is difficult to choose between many choices or alternatives to make a decision. (Check out example – Criteria matrix)


Conclusion – 

Group decision-making techniques are essential to reach the final conclusion with the consensus of all project team members. These techniques make it easy to perform problem-solving discussions without conflict among team members. It helps the project teams increase the speed of decision-making effectively.

I have shared the most useful 5 techniques of group decision-making with you which can help you during your Six Sigma projects or any type of improvement project to make better decisions as well as prioritization of problem-solving ideas. I hope you got the clarity on these techniques.

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