Why Kanban? Why focus on lead time reduction?
I believe that why we would use a kanban system and why the Kanban Method is an appropriate approach to change are worth re-iterating.
ROOT CAUSES
The root causes are that knowledge workers such as software developers are overburdened, and that they suffer from interruptions, task switching and too much multi-tasking as a result of the overburdening. The overburdening comes from a drive to manage for efficiency (or utilization), that knowledge work is invisible and because the future is uncertain and hence we must always generate more options than we will eventually use or need. As a result, demand always exceeds capability to supply, and workers are always busy. Often they start more and more work without a focus on finishing it. This in turn leads to long lead times.
Long lead times are correlated with poor quality. This is almost certainly because the work is done by the chemical computers between the ears of the individuals and much of the knowledge is tacit and stored across a network of individuals and not completely inside the head of any one individual.
Much of the work is invisible and a shared understanding of the work and the dynamics of the process that created it are often not achieved. As a result, mistakes are made! Misunderstanding of invisible work require large amounts of coordination effort to reconcile and rework is often needed. Insuring quality and an outcome that matches with original expectations is a constant challenge.
THE VALUE OF REDUCING LEAD TIME
Early delivery of knowledge work often creates additional value. However, regardless of whether early deliver creates additional value or not, shortening lead times (or cycle times within a single function or activity) is almost always desirable.
Short lead time (or local cycle times) demonstrate agility. They also create liquidity in the system. Hence, short lead times (or cycle times) are desirable from a risk management perspective. If this can be achieved while avoiding managing for utilization then the idleness that occurs provides options (and liquidity) improving risk management and responsiveness of the business.
KANBAN SYSTEMS
Kanban systems enable us to limit WIP and avoid overburdening by only pulling work when there is capacity. Due to the variability in work and the dynamics of the process, limiting WIP, will result in idleness of some people and an inability to perform some of the activities in the workflow. Idleness is a signal that there is an opportunity for improvement. Idleness also provides slack with which to make improvements.
Kanban visualizations enable workers to engage their emotional intelligence to see (and feel) the work and the dynamics of the process. This helps immensely with shared understanding reducing coordination effort and improving quality.
Limiting WIP reduces lead time by reducing multi-tasking. Other kanban system design strategies and staff allocation strategies may reduce task switching. Altogether these improve quality. This is almost certainly because knowledge work is processed by human brains (chemical computers) and the interactions of team members. Knowledge is often stored between and across members of a network. By keep the time from starting to finishing short, the risk of knowledge perishing or information becoming stale due to external forces, is greatly reduced. The result is a better product and usually a lot faster.
Kanban provides us with metrics that allow us to observe/study the capability of the kanban system and to manage it in a probabilistic fashion. This enables us to make promises we can keep and results in increased social capital (trust) in the wider organization. More trust leads to greater collaboration and this can provide the political capital to enable larger bigger changes that result in even greater improvements.
THE KANBAN METHOD
What is needed to enable all of this is documented on the cover page for this Yahoo! group and in the book, Kanban – Successful Evolutionary Change for Your Technology Business – namely…
- Visualize
- Limit WIP
- Manage Flow
- Make Process Policies Explicit
- Implement Feedback Loops
- Improve Collaboratively (using models & the scientific method)
It has been observed that teams and organizations following these 5 practices have often (though not always) exhibited a series of improvements in capability and a culture of continuous improvement.
To lead a cultural change and generate improvements with kanban systems, to use The Kanban Method, an organization should follow the core principles of…
- Start with what you do now, respecing current process and roles
- Agree to pursue incremental evolutionary change
- Encourage acts of leadership at all levels
IS LEAD TIME THE ONLY CAPABILITY WE CARE ABOUT?
No probably not! We care about throughput (expressed as value items delivered per period of time). We care about quality. We care about the social capital of the organization. We care about customer satisfaction. We care about governance and risk management of the organization.
What we care about is always contextual and has to be based on a mix of customer and other stakeholder expectations.
However, lead time is nearly always one of them because it provides benefits in so many dimensions of risk that reducing lead time nearly always improves the satisfaction for one or more stakeholders.
