I love using burndown charts, but they only work for finite chunks of work.
Since I also help out groups that do continuous operational work, I wanted to develop a similar tool that would work for them. In operations, the task list is a producer-consumer queue that fills at one end and is depleted from the other. So this is what I use.
Along the horizontal axis are labels for blocks of time, similar to sprints. The vertical axis shows the number of work items, or the cumulative size of the work items.
At the end of any given time block, there will be some items not yet completed. These are added to the pile, and the chart gets higher. As those items are completed in future time blocks, they are removed from the chart.
The total height of the stacked areas represents the number or cumulative size of all work items "on the go" at that time. The height of any specific area section shows the number of work items remaining from the period where they were introduced. Counting the number of coloured zones in any vertical cross section shows how many old time blocks still have something lingering around.
The best part is that slope becomes a powerful indicator of velocity and focus. It encourages you to get rid of the oldest items, so that items from old time blocks are visibly wrapped up. As the pace of work increases, the slope becomes steeper and steeper.
Here's the question: Is there a name for this kind of chart? I'm having trouble finding similar examples. I've been referring to them as "continuous burndown" or "stacked work" charts.