Post mortem technique

Two interesting tricks I saw in a postmortem I just attended:

Take a poll via anonymous sticky note poll on the relative safety in the room:
4 - Secure: I can share everything
3 - Safe: I can share almost everything without filtering
2 - Neutral: I can share most of what I want to share without filtering
1 - Dangerous: I cannot share some of my important contributions in the room.
0 - Treacherous: I cannot share most of my important contributions in the room.

Then talk about what ground rules could be put in place to help this.  Then up/down thumb vote to confirm everyone agrees to abide by those rules.

The other was to do a Return on Time Invested (ROTI) at the end of the meeting:

5 - Awesome!
4 - Exceeded expectations
3 - Was worth the time invested
2 - Wasn't worth 100% of the time invested, but worthwhile
1 - Not worth my time