I think complex decisions should be made via discussions on shared documents (Google docs, Microsoft Word, text files with version control, etc…) when possible. A document provides the context for the decision being made, and the comments allow for discussion on the various inputs to the decision. Version control can provide information about how the thinking around the decision has changed over time.
Well documented decisions also provide the following benefits:
- Future readers can understand how a decision was made, and if assumptions that were inputs to that decision have since changed.
- New team members are more easily onboarded.
- Institutional knowledge is preserved.
Email has similar advantages, but the format often makes it harder to follow the most recent thinking on a decision. The context is not as readily available, and fully understanding the context often involves reading through a long chain of potentially poorly formatted emails (even without top posting).
Meetings can be a forcing function if a decision needs to be made quickly. However, the loudest voices often have an outsized influence, and the specifics of the decision are often lost, even with extensive and accurate meeting notes.