4. Converge

After the idea generation phase, you will have a large set of ideas. How to now select the most promising ones? The first step is often a form of grouping (to create an overview, discover themes, and filter out noise), followed by some form of voting for the actual selection.

Photo by Josh Evnin. CC BY-SA 2.0

Affinity grouping (Clustering)
Put exactly the same ideas on top of each other (be careful though: are there perhaps some key differences that you do not want to lose?). Put similar ideas next to each other. The participants can do it themselves, or the facilitator can do it immediately when an idea is posted up. Decide on a name for each cluster that represents its main shared characteristics. When the clustering is done, call the names for each cluster out loud and quickly summarize its contents, so everybody knows what is now on the board.

DOT voting
Give every participant a fixed number of votes (for example 3 or 5) they can assign to the ideas of their choice. You can use round stickers or have people draw circles with markers.
An interesting variation to this method is to first discuss the criteria for good solutions (cheap, fast, ...?) before everybody casts their votes.

Anonymous voting
To prevent participants from getting influenced by other people's votes, people can also vote anonymously. Simply have everybody write down their top 3 (or 5) ideas for themselves. Gather all the votes and determine which ideas were the most favorite.