What Is It?
The Aging Work in Progress (WIP) chart, sometimes called the Aging chart, displays the age of active work items in your process.
Before we go any further, let's define the term age of a work item:
Work item age: The amount of elapsed time between when a work item started and the current time.
Part 1 - Anatomy of the Chart
The chart comprises your process's columns on the X-axis, while the Y-axis displays the work item age. The image below shows the five columns of our process on the X-axis and the age in days on the Y-axis.
We then plot our active work items on the chart. For example, we have an active eight-day-old work item in the Building column. It is drawn like this on the chart:
All your active work items are then plotted on the chart, as seen in the following image. The Y-axis shows that the age of the active work items is no higher than 20 days.
Since your columns can have many work items, we've added an extra label on the chart. This label has the WIP abbreviation and the number of active work items in each column. The label does not refer to the WIP limits of each column.
On the image below, we can see that the To-Do column has nine active work items by looking at the label "WIP: 9."
The final piece of information that we need to add is the percentiles. Remember how those percentiles were used in the cycle time scatter plot chart to forecast a work item? We use the same percentile lines against our active work items in the Aging WIP chart.
In other words, we track the age of our active work items against our historical completed work items. This tracking helps you have a proper conversation about work items getting too old based on the initial forecast you gave to your customer.
Notice how two work items in the "Validation" column are above the 85th percentile line in the image below. This information could indicate they are late and need more attention than, let's say, the three work items at the bottom of the "Discovery" column.
PaceMkr creates this chart for you with your active and historical data. Here is what looks like an Aging Work In Progress chart in PaceMkr:
Part 2 - Looking at an active work item
You can additional information on each active work item by moving your mouse cursor on a data point. Here is an example of an active work item tooltip:
An active work item tooltip has the following information:
- Identification (in bold at the top): Contains the work item ID and a link to the work item page in your project.
- Description: This is the description of the work item.
- Age: The current age of the work item.
- Start date: The date at which the work item started.
- Columns: The number of days the work item spent in each workflow column.
In addition to this tooltip, PaceMkr highlights the number of days this work item spent in each column. In the image below, we can see this with blue bars being covered in specific areas of each column.
Part 3 - Percentiles lines
The Aging WIP chart also has the same percentile lines that on the cycle time scatter plot chart. These are the horizontal lines and can be hidden with the toggle button under the chart.
In the cycle time scatter plot tutorial, we explained how these lines are created and used for setting the Service Level Expectation. In the Aging WIP chart, these lines can be used as a way to respect the Service Level Expectation.
For example, work item 10102 in our screenshot above has an age of 20 days which is between the 85th and 95th percentiles lines. If your Service Level Expectation in your team is 95%, it means your work item is 5 days from going over your forecast of 25 days or less, 95% of the time. You then have 5 days remaining to complete this work item. If your SLE was the 85th percentile line, which is 17 days or less 85% of the time, it means your work item 10102 is over your forecast and needs attention right away.