If you have spent any time in manufacturing, you have probably heard of the book The Goal and the Theory of Constraints.
The central idea is simple: every system is limited in achieving its goal by at least one constraint, or bottleneck. Improving anything other than the constraint has limited impact on overall system performance.
Simply put, every process has a point where work slows down. That bottleneck determines how much the entire system can produce. If you want to improve the system, that is where you should focus your energy.
One of the appealing aspects of the Theory of Constraints is that finding the bottleneck usually is not difficult. Look for where work piles up, where people are constantly overloaded, or where items spend the most time waiting. Once you identify the constraint, improving it often produces outsized results.
Organizations frequently make the mistake of optimizing individual steps rather than the system as a whole. Email is a good example. Email makes it easier to push more work into a process, but it does nothing to increase the capacity of the bottleneck. In many cases, it simply increases work in process and creates a larger backlog somewhere downstream.
I have seen this happen when organizations hire support staff to free up engineers. The additional support capacity often allows more work to enter the system, but it just creates a logjam at the next step.
From a Lean perspective, these growing queues create additional waste that the organization must eventually manage. From a human perspective, they create stress. People at the bottleneck become overwhelmed while everyone else wonders why the system still feels slow despite all the improvement efforts.
Before investing time and money in improving a process, it is worth asking a simple question: where is the constraint? If you are not improving the bottleneck, you may simply be moving the problem rather than solving it.