Brainstorming asynchronously on a shared doc of some sort (google doc, miro board, even slides) is way better. Kick off with a meeting to set some parameters and answer questions, then let everyone enter ideas at their leisure for a week and regroup to dicuss.
The most effective seems to be to do the first round independently, IE each person come with their 2-3 best ideas before collaboration. Otherwise there's a strong tendency to just +1 existing ideas rather than think independently.
I was going to say this exactly. We've started doing this recently and it's worked really well.
We'll start off with a topic and give everyone, say, 15 minutes to write ideas in the doc on their own. Then take the next 15 minutes to read digest what everyone else wrote, and then rest of the time to discuss as a group.
It's great because it gives everyone a chance to think through the topic and share their perspective, but also you can quickly see the common themes.
