If the issue does not have sub-issues:
If the issue does have sub-issues:
If the issue has both its own status and sub-issues with progress, and if Ignore Parent Issue Progress is turned off, issue's own progress value is counted as if was the progress of one another sub-issue.
If some of statuses don't have any percentage configured, issue progress is considered undefined.
In this example, statuses have the following percentages: Open = 0%, In Progress = 50%, Resolved or Closed = 100%, Reopened = 80%. Apply Resolution is turned on, Ignore Parent Issue Progress is turned on.
This issue is Open, so it is 0%
This issue is In Progress, so it is 50%
This issue is Resolved, so it is 100%. Also, according to workflow, it has non-empty Resolution, which also means it's complete.
This issue is Close, so it is 100%. Also, according to workflow, it has non-empty Resolution, which also means it's complete.
Average progress is (0+50+100+100)/4. Issue's own status is In Progress, but it's percentage is ignored because of "Ignore parent issue progress in aggregation" option
This issue is Reopened, so is 80%
This issue is Open, so is 0%
Average progress is (80+0)/4 = 40%. But issue itself has Resolution and "Issues with Resolution are 100% done" option is turned on, so this overrides sub-issues progress and makes issue complete
It has two sub-issues: sub-issue 1 is 63% done and sub-issue 2 is 100% done. Average progress is (63+100)/2