Advanced Product Management
Prioritizing the Product Backlog
Queuing Theory, Theory of Constraint, and Eliminating Bottlenecks
In any system where there is a finite capacity to process work, there will be bottlenecks. Bottlenecks are resources or processes that limit the throughput of the system. They can cause delays, frustration, and lost productivity.
Queuing theory is a mathematical discipline that helps us to understand how bottlenecks work. It provides us with tools to analyze the flow of work through a system and to identify the bottlenecks.
The theory of constraints (TOC) is a management philosophy that helps us to manage bottlenecks. It teaches us to focus our efforts on optimizing the performance of the bottleneck resources.
By understanding queuing theory and TOC, we can learn how to identify and eliminate bottlenecks in our systems. This can lead to significant improvements in throughput, productivity, and customer satisfaction.
How Queuing Theory Works
Queuing theory models a system as a network of queues or product backlogs. Each queue represents a resource or process in the system. The resources or processes are connected by links. The links represent the flow of work between the resources or processes.
The queuing theory model can be used to calculate the following:
The average wait time in each queue, known as Lead Time
The average throughput of the system, known as Cycle Time
The probability of a customer having to wait in a queue
How the Theory of Constraint Works
The theory of constraint (TOC) identifies five steps for managing bottlenecks:
Identify the system's constraints.
Decide how to exploit the constraint.
Subordinate everything else to the constraint.
Elevate the constraint.
Repeat steps 1-4 until all constraints are eliminated.
The first step is to identify the system's constraints. This is the resource or process that limits the throughput of the system. Once the constraint has been identified, the next step is to decide how to exploit it. This means finding ways to make the constraint work as efficiently as possible.
The third step is to subordinate everything else to the constraint. This means that all other resources and processes in the system should be aligned with the constraint. They should not be working on anything that is not essential to getting work through the constraint.
The fourth step is to elevate the constraint. This means finding ways to increase the capacity of the constraint. This can be done by adding more resources, by improving the efficiency of the constraint, or by changing the way work is processed through the constraint.
The fifth step is to repeat steps 1-4 until all constraints are eliminated. This is an ongoing process, as new constraints will inevitably emerge over time.
Eliminating Bottlenecks
By understanding queuing theory and TOC, we can learn how to identify and eliminate bottlenecks in our systems. This can lead to significant improvements in throughput, productivity, and customer satisfaction.
Here are some tips for eliminating bottlenecks:
Identify the bottleneck. The first step is to identify the bottleneck resource or process. This can be done by using queuing theory or by simply observing the system.
Exploit the bottleneck. Once the bottleneck has been identified, the next step is to exploit it. This means finding ways to make the bottleneck work as efficiently as possible. This could involve adding more resources, improving the efficiency of the bottleneck, or changing the way work is processed through the bottleneck.
Subordinate everything else to the bottleneck. Once the bottleneck has been exploited, the next step is to subordinate everything else to the bottleneck. This means that all other resources and processes in the system should be aligned with the bottleneck. They should not be working on anything that is not essential to getting work through the bottleneck.
Elevate the bottleneck. The fourth step is to elevate the bottleneck. This means finding ways to increase the capacity of the bottleneck. This can be done by adding more resources, by improving the efficiency of the bottleneck, or by changing the way work is processed through the bottleneck.
Repeat steps 1-4 until all constraints are eliminated. This is an ongoing process, as new constraints will inevitably emerge over time.
By following these tips, you can learn how to identify and eliminate bottlenecks in your systems. This can lead to significant improvements in throughput, productivity, and customer satisfaction.
To go deeper on these topics, consider Donald Reinersten's: "Product Development Flow" and Eli Goldratt's "The Goal"