Card clustering

Tool 48 – Download here

Aim of the tool
To quickly generate and cluster ideas, synthesize ideas, encourage discussion and consensus.

When to use it?
The tool can be used in various stages of a MSP, but particularly in the Convergence stage. The tools is effective in groups that are diverse or have diverse opinions on an issue, as well as when hierarchies are present.

What is Card Clustering?

Card clustering is a facilitated process that involves the use of cards (or post-its) to gather ideas from people, especially when a diversity of answers is expected. The tool is useful for groups of between 12 – 20 people; larger groups may be sub-divided into smaller groups. Starting with a question, ideas are captured onto cards and later clustered based on similarities. Once these clusters are labelled, they can be prioritized or elaborated further.

Card clustering is very useful for synthesize group ideas, encouraging consensus and prompting discussion. An important advantage of the tool is that it encourages all participants to give their feedback, including those who would normally stay quiet in group discussions.

How to use Card Clustering

There are many ways how to use cards in meetings. The basic routine goes as follows:

  • Introduce a question to the group.
  • Participants write their ideas concerning the question on cards (eg. maximum of 3 cards per person). Each participant will individually write their cards. Rules for card writing:
    • Think before writing.
    • One idea per card
    • Use short statements. Avoid full sentences or single-word cards.
  • As a facilitator, invite participants to share their cards with the group by reading them out loud and clarify briefly if needed.
  • Gradually, all cards are placed on flip-over paper, on a wall or on the ground so that everyone can see them.
  • Cards will then be discussed by the group and clustered based on similarities. Make sure that there is unanimity about the clusters and the cluster names.
  • Once the clusters are labelled they can be further elaborated and discussed.


If the topic is sensitive, it is possible to use cards anonymously to ensure that participants will still share their ideas. In this case, the facilitator will collect and read the cards.

In large meetings, you can ask sub-groups to discuss the issue and come up with a limited number (e.g. 3) of cards representing the groups’ ideas. Only sharing these cards reduces valuable plenary time, while still including everyone’s input.

It can be time consuming and complex to reduce the number of ideas (cards) to a manageable number. We often use a technique called FastBreak, created by Bob Williams, to do this. All cards are numbered and you ask for someone to nominate a pair of numbers which seem to go together. By continuing to call for new pairs that participants nominate (“23 goes together with 8”), you will see clusters starting to emerge.

A main challenge with card clustering is managing time, without compromising the participatory nature of the tool. It is tempting to help the group by proposing clusters or cluster names, but only do so after you have consulted with the group. It is better to take a bit longer, and build a shared analysis, than have a perfect set of clusters which only a few people can explain or agree with.

The results of a card clustering exercise are usually a good start for further small group work (“Which people want to spend an hour to further analyse the issues in cluster 1, and who signs up for cluster 2, 3 or 4?”).

Photo: Clustering cards as a way to choose priorities for a regional strategy of ICCO South Asia (CDI, 2011)

Learn more

Salas M A, Tillmann H J, McKee N and Shahzadi N (2003) Visualization in Participatory Programmes VIPP How to Facilitate and Visualise Participatory Group Processes Bangladesh: Southbound for UNICEF.