Thesis
Most product decisions are often made in silo by the product manager of a team based on a combination of analytics, user sentiment, market dynamics or competition
This often results in a product manager writing a product spec laying out the conditions on the user story and the solution
Product manager then (usually) reviews this with their team and manager before working with the engineering/design team to execute this
Product manager might share this with other PMs but more often than not the other PMs are too busy to review the spec and add their commentary
Hence, the brunt of the responsibility lies on the manager to ensure this is the right product to ship. The manager is steeped in context and often lacks the open mind to truly debate the hypotheses and solution and usually the PM (and their manager) opts for the best solution discovered by them
However, this solution may not be the best "overall" solution since:
It was a small group of people steeped in context making the decision
Most decisions are consensus-based and most people are afraid to voice their true opinion
Thesis: To truly make the best decision, you should be debating this with other folks in the company who are not as deep in the problem as you are
Debate format
Note: This works best for 4 people, but can be modified for 3 or 5 as well. Small groups are best
PM writes a 1-pager of the product spec with basic context (goal/metric), problem and solution chosen - it should not be longer than 1 page but should have enough to have a conversation
PM sends this the night before the day of the meeting. People leave comments async in the doc. Of the three people remaining, one person will support the PM and the solution. The other two will try to find other solutions and debate why those other solutions are better
Supporting PM has the hardest role since they need to truly believe and find merits of a spec she/he hasn't written. The supporting PM also plays the role of the note-taker
Opposing pair need to spend time ahead of time figuring out alternative solutions to provide a different perspective
Here's how 30 mins usually go:
5 min - read the 1-pager and ask any clarifying questions that are useful for the group
5 min - PM and supporting counterpart make the case for why this is the best path forward
5 min - Opposing PMs make the case for why their alternative solution(s) is the best path forward
10 min - Discussion on what the merits of each path is and trying to narrow down options
5 min - PM who wrote the spec summarizes discussion and next steps
Recommend meeting on a recurring basis (weekly, once in two weeks or max monthly)
Principles
Goal of the debate is to help the PM build the best product for the customer that balances business considerations as well
Leave ego and relationships at the door - what happens in the meeting, stays in the meeting
No need for mental aerobics - debate only if you have valid points, not to score points
Raise your words, not your voice
Write down as much as you can - helps summarize discussions later