I have another rule, along similar lines: Never introduce new information at a meeting.

We tend to decry "politics" as a dirty thing, and I'm no great fan of dysfunctional organizations. But even among bright, innovative people, I've observed what I think is the root cause of your rule:

Most people, especially managers, really don't like to debate and negotiate in front of an audience.

I'm like that myself. I think (could be wishful thinking of course) that I'm a high performer. But I'm a terrible debater. I'm not quick with facts, and I don't handle the emotional pressure of debate very well. I'd probably flunk a coding interview. I prefer to sit down and think something through, and to access the information that might not have been presented by the debaters. And in any event, I've noticed that most conclusions reached through debate in meetings are simply overturned by facts later on.

I agree. I also believe there are other good reasons for this rule. Imagine : 15 minute whiteboard workshop - "capturing value from meetings". We draw a horizontal line on the board, a relative value scale, lower to the left, higher to the right. Then we shout out a bunch of stuff people do in meetings, write them post it notes and try and arrange them on the scale. Once the stream starts drying up, draw a vertical line in the middle of the scale. It will now be reasonably obvious that what's clustered on the left can be loosely categorised as 'shit you could have emailed me' and what's clustered at the right as 'spontaneous interaction of informed participants'. Likely you can now demonstrate that stuff at the left - despite perhaps having intrinsically high value - is likely subtracting value in the context of a meeting. If you have good intuitions or hard data on time and travel, you can probably come up with a cost estimate.

I recommend trying this exercise with real people with the caveats that a) some of them will become angry, and b) probably most of them will ignore the outcomes unless you have some way of incentivising them not to.

These two comments are great! Thanks!