The affinity diagram is another simple to I use tool to organize topics into logical categories.  It is very useful and easy to do during a brainstorm session in front of a whiteboard and typically is very efficient.

You start by writing the subject of the brainstorm.

Then write down all the items you can come up with and that you think are related to the subject.

Once you have a good number of items, bundle them into categories.

Finally, look at the list of categories and apply the MECE approach to make sure that you’ve sufficiently covered all the categories.

It works great with a team of cross-functional people to make sure that you’ve covered all the bases and can be done in a very short session if done well.

Finally, you can come up with the categories first, but this comes with the same advantages and inconveniences as we discussed in the Fishbone Diagram post.