One thing that is often† encountered during the lean process, and in life every day, is the challenge of finding the best possible solution to any problem. Lean is really nothing more than applying problem solving thinking to the challenges of individuals, teams, groups, and entire organizations, and inevitably you will come to the fork in the road where a decision is needed on a countermeasure. One thing that has taken a very long time for me to really understand is that there is no “one best way” to do anything. Every choice and possibility has both pros and cons. Everything‡ is a trade-off.
Think about this in the physical world. In aircraft for example, there is a trade-off between lift and drag. Lift is needed for the plane to actually fly, and typically† a larger wing with a larger profile (airfoil shape) will provide greater lift, and thus lift a heavier plane. But the larger wing also causes more contact with wind and resistance (like a bicycle rider sitting straight up) and thus more drag. Increased drag requires more power to overcome the effects (just like it is harder to pedal a bike with a strong head wind), but that comes with the trade-off of increased fuel consumption.
All is not lost though! It is possible to find the proverbial “sweet spot” where the variables are optimized. The important things to bear in mind are that the ideal perfect condition does not exist and you can stop wasting time searching for it and instead invest your time in identifying both sides of every proposition and “gather the facts, and weigh and decide.” This is a lesson I learned from Toyota, but originated in the Training Within Industry programs (Toyota did not really invent most of the ideas that they use, and they openly acknowledge that fact. They do a very good job of applying the ideas though.)
Here is a similar conundrum that sometimes confuses people trying to implement lean. This is the condition of declaring one “rule” such as the elimination of waste, but then in some cases appear to (I use the word appear here because sometimes it is necessary to step back and consider the entire process to determine whether the total waste has been increased) add waste. Or similarly declare the seven types of waste as the enemy, and then build a system to manage one of the wastes (declaring inventory as waste and then creating a supermarket of inventory).
It is necessary to think of these issues not as contradictions, but rather trade-offs. If we consider the total situation we can see that it may produce a preferred result to trade one thing for another (least of two evils). A simple example is when creating a cell we often increase the waste of motion (walking). Previously a person may have been stationary and now they walk between multiple operations. On first glance it may appear that the person is spending a fair bit of time walking and that is wasteful, but if we look from the perspective of total efficiency of labor* it is a better trade.
One glaring apparent contradiction within the Toyota Production System (TPS) is the concept of heijunka (smoothing of the production schedule) versus the concept of just in time. Just in time suggests that something is only produced at the moment it is needed, while when applying heijunka we usually† create a pattern or sequence of production that allows for a more even distribution of work times so that the flow is more consistent and balanced. The pattern is established by actual work conditions (work cycle times mainly) and is not based on the actual requirement in the exact moment (like just in time).
How is it possible to reconcile this apparent contradiction? We need to consider and interpret the intent of the concept. What we need to say is that we want to produce a product or provide a service as close as possible to the actual need of the customer, and to level the work load as much as possible. Since these two concepts are on opposite sides of the trade-off it is necessary to find the sweet spot between them.
If the determined pattern for heijunka is perfectly balanced we are not likely to provide the proper mix of products (too many of some and not enough of others). If just in time is followed perfectly there will be significant spikes in the work loads and flow will be turbulent and not smooth (creating more waste). It is necessary to find a pattern that provides the smoothest flow and balanced work in the shortest possible time window. Depending on the situation that pattern may repeat hourly, daily, bi-weekly, weekly or even longer. There is no “correct” lean answer (except “it depends” and then it is necessary to define what it depends on), but the two sides need to be considered. It is necessary to gather facts on both sides of the trade and then to weigh and decide where the optimal spot is.
One thing I like about the lean philosophy is that I no longer have to worry about getting the “right” answer to such dilemmas. For one thing there is no such thing as the “right” answer. For another the concept of continuous improvement means that whatever point is established today is only the best we can do today. If we apply kaizen and improve the flexibility of the process and make it more responsive to the inherent fluctuations (an adaptive process) it will be possible to tighten the pattern and bring it closer to actual just in time. That is the method of driving continuous improvement.
* Something to consider is the objective. Toyota does not typically place efficiency as the primary objective. In this case there is an overlying philosophy regarding the value of the human. It is considered a form of disrespect NOT to provide the person with an opportunity to add value, so if an operator is standing and watching a machine operate it is considered disrespectful to that person. In a sense it indicates a higher value placed on the machine. So the trade-off is the addition of a small amount of waste for the ability of the operator to make a greater contribution (considered an honor). As with any trade-off there are pros and cons and along with the greater contribution of the person comes a higher efficiency. This was considered a secondary result by Toyota, and not the primary intent.
†Notice the use of words such as normally, typically, and usually. In some contexts those words are descriptions of a process that is not in control (as in “normally it is not like that), but in this context it is important to note that there is always an exception to every situation unless it is a physical law.
Check back for a future post dealing with this conundrum- for (nearly) every “truth” or “rule” proclaimed there is an exception. Even in that sentence I had to state the exception to what I was saying. There are some physical laws of the universe that thus far we have not found exceptions to. They are typically referred to as “laws” such as the laws of thermodynamics and thus far are immutable (there could be an exception that we have not discovered- I am betting on that possibility, but may have to wait a while!). Rules are made to be broken, but laws (not the man-made ones like the speed limit) are another story.
‡The use of words like everything, always, and never are in fact a contradiction. If everything is a trade-off, that goes against the rule that everything has an exception. It would be more correct to say that most things are a trade-off or most things have exceptions, but I use terms heard in everyday language and it is my contention that we need to learn to be more careful and specific in our language so as to avoid confusion of meaning and intent. We’ll save that conversation for another day!