The Theory of Constraints (TOC)

Strengthening Your "Weakest Link"

The Theory of Constraints (TOC) - Strengthening Your

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Manage your weakest link.

No matter what industry you work in, there is often scope for boosting overall performance. A great way of doing this is to identify and eliminate "bottlenecks," or things that are holding you back.

But how do you identify these bottlenecks?

One approach is to use the Theory of Constraints (TOC). This helps you identify the most important bottleneck in your processes and systems, so that you can deal with it and improve performance.

In this article, we'll explore the Theory of Constraints, and we'll look at how you can apply it to your own situation.

Understanding the Theory

You've likely heard the adage, "A chain is only as strong as its weakest link," and this is what the Theory of Constraints reflects. It was created by Dr Eli Goldratt and was published in his 1984 book "The Goal."

According to Goldratt, organizational performance is dictated by constraints. These are restrictions that prevent an organization from maximizing its performance and reaching its goals. Constraints can involve people, supplies, information, equipment, or even policies, and can be internal or external to an organization.

The theory says that every system, no matter how well it performs, has at least one constraint that limits its performance – this is the system's "weakest link." The theory also says that a system can have only one constraint at a time, and that other areas of weakness are "non-constraints" until they become the weakest link.

You use the theory by identifying your constraint and changing the way that you work so that you can overcome it.

The theory was originally used successfully in manufacturing, but you can use it in a variety of situations. It's most useful with very important or frequently-used processes within your organization.

Applying the Theory

Let's look at a step-by-step process for using the theory:

Step 1: Identify the Constraint

The first step is to identify your weakest link – this is the factor that's holding you back the most.

Start by looking at the processes that you use regularly. Are you working as efficiently as you could be, or are there bottlenecks – for example, because your people lack skills or training, or because you lack capacity in a key area?

Here, it can help to use tools like Flow Charts, Swim Lane Diagrams, Storyboarding, and Failure Modes and Effects Analysis to map out your processes and identify what's causing issues. You can also brainstorm constraints with team members, and use tools like the 5 Whys Technique and Root Cause Analysis to identify possible issues.

Remember that constraints may not just be physical. They can also include intangible factors such as ineffective communication, restrictive company policies, or even poor team morale.

Also bear in mind that, according to the theory, a system can only have one constraint at a time. So, you need to decide which factor is your weakest link, and focus on that. If this isn't obvious, use tools like Pareto Analysis or Queuing Models to identify the constraint.

Step 2: Manage the Constraint

Once you've identified the constraint, you need to figure out how to manage it. What can you do to increase efficiency in this area and cure the problem? (Goldratt calls this "exploiting the constraint.")

Your solutions will vary depending on your team, your goals, and the constraint you're trying to overcome. For example, it might involve helping a team member delegate work effectively, modifying lunch breaks or vacation time to make workflow more efficient, or reorganizing the way that a task is done to make it more efficient.

Here, it's useful to review approaches used in Lean Manufacturing, Kanban, Kaizen, and the 5S System to see if these can help you manage your constraint.

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Again, you'll also find it useful to brainstorm possible solutions with people in your team, and to use problem-solving tools such as the Five Whys and Cause and Effect Analysis to identify the real issues behind complex problems.

Step 3: Evaluate Performance

Finally, look at how your constraint is performing with the fixes you've put into place. Is it working well? Or is it still holding back the performance of the rest of the system?

If the constraint is still negatively affecting performance, move back to step 2. If you've dealt with the constraint effectively, you can move back to step 1 and identify another constraint.


Remember that the theory says that every process has at least one constraint. While this may be true, be sensible in how you apply the theory – sometimes removing this constraint will have a minimal impact on performance.

Key Points

Dr Eli Goldratt developed his Theory of Constraints in his 1984 book "The Goal."

The theory says that every system, no matter how well it performs, has at least one constraint that limits its performance. You use the theory by identifying your constraint and restructuring the way that you work so that you can overcome it.

You can minimize constraints and work more efficiently toward accomplishing your goals by working through these steps:

  1. Identify the constraint.
  2. Manage the constraint.
  3. Evaluate performance.

Be sensible in how you apply the theory – sometimes the effort required to fix a constraint might not be worth the improvement in performance.

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Comments (13)
  • Over a month ago BillT wrote
    Hi Anonymous2,

    I like your extrapolation to the theory using POOGI (Process of Ongoing-Improvement) that was developed by Dr. Goldratt to help clarify his Theory of Constraints. Great feedback.
  • Over a month ago Anonymous2 wrote
    There are actually 5 steps to this, called "The five focusing steps". These are:
    1. Identify constraint
    2. Exploit constraint (get the most out of the already available resources)
    3. Subordinate to the constraint (ensure all other "links" don't over produce causing temporary bottlenecks)
    4. Elevate constraint (add more resources if necessary)
    5. Repeat (don't let inertia slow down continual improvement)

    Evaluating performance is implied in all steps as it helps you determine when to move to the next step, but it is not a step on its own.
  • Over a month ago Michele wrote
    Hi Kinberley,

    The Theory of Constraints may help you to improve the efficiency and effectiveness of your processes in such a way that the workload of your reduced team is manageable. I have participated in a few process improvement projects resulting in significant productivity improvements.

    Mind Tools Team
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