Control Chart seems wrong after turning on Kanban backlog

[Glen Tan]

I recently turned on Kanban backlog as I wanted to clearly show what was truly in the todo and leave everything else I didn't want to show on the board in the backlog. In the process I created a ToDo column and moved what I wanted into that. Now when I run the control chart over any period since, when I exclude the new ToDo column it actually increases the average cycle time, when I would have thought it would reduce it. 

[Bill Sheboy]

Hi @Glen Tan 

What is probably happening: with the ToDo column, those items were counted in the total items (the divisor), and so reduced the average.  When you remove Todo items, the count goes down and so the average goes up.

This makes sense if Atlassian is using a purist interpretation of the board and Kanban.  Because the leftmost column (ToDo) is part of your workflow (and not in the backlog).  So all columns on the board would initially be fair game for cycle time calculations.  (Lead time would start even earlier: when the issues were added to the backlog)

Depending on the number of items on the board, you can verify this by hand on paper.

Best regards,

Bill