What is a Bottleneck?
A bottleneck is a specific point in a process where the flow of work is limited due to insufficient capacity or lower efficiency compared to other parts of the system. It slows down the entire process, just like a narrow part of a bottle limits how fast the liquid can pour out.
Key Features of a Bottleneck:
- Usually a machine, person, or task with limited output
- Can change frequently depending on conditions
- Has a local impact but can affect the entire system
- Often visible and measurable
Example:
In a manufacturing line, all machines produce 100 units/hour, but one assembly machine can only process 60 units/hour. This assembly machine is a bottleneck because it limits the total throughput of the system.
What is a Constraint?
A constraint is anything that prevents the system from achieving its goal. It can be physical, like a bottleneck, or non-physical, like a policy, market demand, mindset, or regulation. The concept of Constraint is central to the Theory of Constraints (TOC), which focuses on identifying and improving the most critical limitation in a system.
Key Features of a Constraint:
- System-wide limitation that restricts performance or output
- Can be physical, policy-based, market-related, or behavioral
- Requires a strategic and systemic approach to resolve
- Is persistent until addressed through the TOC’s 5 Focusing Steps
Example:
A company has enough production capacity but can’t grow because the market demand is low. In this case, the constraint is external (market), not internal.
Bottleneck vs Constraint: Key Difference
| Aspect | Bottleneck | Constraint |
|---|---|---|
| Definition | A resource or step that limits flow temporarily due to capacity | Any factor (physical or non-physical) that limits the system’s goal |
| Scope | Usually physical and local to a process | Can be physical, policy-based, market-driven, or even behavioral |
| Frequency | Can change frequently due to short-term issues | Usually the most limiting factor system-wide until resolved |
| Type | Often machine, labor, or workstation with lower capacity | Could be a bottleneck or policy, mindset, supply chain, or market |
| Solution Focus | Usually fixed by local optimization or capacity increase | Requires systemic change or TOC’s 5 Focusing Steps |
5 Relevant Examples of Bottleneck vs Constraint
🏭 Example 1: Manufacturing Plant
- Bottleneck: A CNC machine that processes only 10 parts/hour while upstream machines produce 20 parts/hour.
- Constraint: A government regulation limiting the total daily energy usage across the plant, affecting all production.
🚚 Example 2: Logistics & Delivery
- Bottleneck: A specific delivery van is under maintenance, delaying shipments.
- Constraint: Company-wide policy that restricts deliveries only during daylight hours, reducing total delivery window.
🏬 Example 3: Retail Inventory
- Bottleneck: Stockroom staff shortage on weekends slows down shelf replenishment.
- Constraint: A flawed supply chain contract allows restocking only once a week, limiting product availability.
📈 Example 4: Sales Operations
- Bottleneck: Only one salesperson is trained to close enterprise deals, delaying large client onboarding.
- Constraint: Market demand in a specific region is saturated, limiting growth potential regardless of sales capacity.
🖥️ Example 5: IT & Software Deployment
- Bottleneck: A single QA tester is delaying the release of software updates.
- Constraint: Organizational approval policy requiring three hierarchical levels to sign off on each release, slowing all launches.
Short Notes
- A bottleneck is often a symptom of a local inefficiency and is typically easier to fix.
- A constraint is systemic, often deeply embedded, and needs a strategic, TOC-based approach.
- Every bottleneck is a type of constraint, but not every constraint is a bottleneck.
- Understanding both helps businesses improve flow, productivity, and profitability by focusing on what truly limits success.
