There is no blocked state in Kanban.
Status of work items on in Kanban is represented in four different dimensions:
- Work item type
- State in the workflow
- Importance in the state
- Indicators of trouble (item aging)
In a properly set up kanban, these four dimensions exist on every item on the board simultaneously. If you create a column to hold items that are in trouble, blocked, red status, or any other indicator of needing attention, then you lose the other three dimensions of reporting that the board gives you on status.
This is usually because the people managing the kanban do not understand the difference between the four dimensions of reporting.
Work item type. Different types of work move through the system at different speeds. A work item type is not a size of work such as S, M, L, XL. The work item type is the kind of work it represents. In any system, there are differing categories of work to perform. In your life, you have work item types of family, personal, and work. At work you have different work items that are personal to you such as compliance training, prepping and delivering facilitated meetings, and projects you have been assigned. These different types of work probably have different expectations for completion. You may later need to differentiate what is happening in your work based on the types that you are doing.
Work state. Every system has steps. Most people make a complicated flow chart with decision points, yes/no divergence, and different flows going in different directions. Those are often complex, beautiful, professional-looking diagrams that are filed away and never referenced. Any complicated process flow that is disconnected from managing work in the process is rarely used and often ignored. In Kanban, the workflow definition and the work itself are both mapped in the same place. A simple, linear, step by step method is used to define the workflow to make clear the states that work goes through.
No decision trees. No branches coming off of a critical path. No diamonds, circles, and squares. Just states that the work goes through. For software development, analyze, design, build, test, deploy, and release are typical states. For home chores, you might only have “doing” as a state. If you assign chores to children and need to review their work, you might have doing, review, pay allowance, as states of work.
Importance. In a typical kanban, cards representing work items are arranged vertically in work state columns in order of importance. The most important things go first. Other things sit lower down and are less urgent to work on. We can clearly see which item is most important because it is at the top level of the state that it is in. Importance can be determined by any number of factors including cost of delay, value x difficulty, size, potential revenue, or weighted shortest job first. Most often importance can be eyeballed and does not require us to use math to determine.
Trouble indicators. In kanban, items are in trouble if they start to age in the system. The goal for getting things done is for work to flow quickly from state to state. If an item ages in place for too long, it is not flowing. A blocked item is one that is sitting there under conditions that prevent it from moving without some sort of intervention by more powerful people or side quests to remove obstacles to completion. Obstacles to completion may be dependencies on other people completing other work. You can’t clean the kitchen while someone is cooking in it. Obstacles to completion may also include more serious dependencies to complete the item, such as an inability to park a car because the parking lot concrete is still drying. Kanban is designed to reveal these problems to you immediately.
By leaving items where they are to indicate trouble, they serve as broken down cars on a highway impeding the flow of traffic, thereby motivating everyone to get out of their cars, fix the problem or push the car off to the side to get it out of the way and continue on. Items that are blocked continue to consume limits on WIP, so if a state can only have three active items in it, and all three are blocked, the solution is not to start three more items and park these three. Instead, attack these three broken down items and get them moving immediately, even if it means stopping everything else. Kanban encourages us to recognize that starting more work while other work is stalled is foolish and causes the system itself to stop flowing.
Moving items to new states that indicate a status strip importance and work state from the item. What happens when the trouble clears? Do we know what state it goes into? What about WIP limits? Are we moving things out of states to clear the WIP limit and have the item moved to the side of the road so we can start other work? When the item clears, how do we put it back? We cannot, so the blocked state becomes a queue that holds waiting work that piles up. This is a form of flow debt that leaves our system slowly shutting down with work backing up everywhere. So much is now going on that people slow down and cannot complete anything that they have.
Leave items where they are and mark them as in trouble rather than pushing them to a special state of “blocked.” Let Kanban not merely show you where work is at, but also how to work more effectively. A healthy Kanban will show you four dimensions of information about items: type, importance, state, and trouble indicators.
