Guide to setting karma thresholds?

[Michael Ekstrand]

I'm working on pushing my first bugfix to F15 (#711261), using the
guides I found in the wiki[1][2].  For a non-critical-path package, the
Update Policy says that it needs to meet the positive karma threshold
set by the submitter, but does not indicate what that threshold should
be or guidance for determining appropriate values.  The default is 3;
I'm assuming that leaving it there is a reasonable thing to do (and I
won't be surprised if the 7-day criteria will be hit first for this
package).

However, I am still wondering: is there any guidance or policy published
on how to determine appropriate karma thresholds?  What justifies
increasing or decreasing the thresholds?  Userbase?  Impact of change?

Thank you,
- Michael

1. https://fedoraproject.org/wiki/Updates_Policy
2. https://fedoraproject.org/wiki/Package_update_HOWTO