Have you ever watched a viral video take off? At first, the view count explodes. It doubles every hour. It feels like it will go on forever. But eventually, the growth slows down. The views trickle in, and finally, the number flatlines.
What happened? Did the video suddenly become “bad”? No. The system simply shifted gears.
In System Dynamics, this is called a Shift in Loop Dominance. Complex systems are rarely controlled by just one force. They are usually a “tug-of-war” between multiple feedback loops. Loop Dominance explains that while many loops exist in a system, only one loop tends to determine the system’s behavior at any specific moment. Understanding when—and why—control passes from one loop to another is the secret to managing growth and preventing collapse.
The Tug-of-War Inside Systems
Most systems contain both Reinforcing Loops (R) and Balancing Loops (B) linked together.
- Reinforcing Loops want to drive change (growth or collapse).
- Balancing Loops want to resist change (stability or limits).
These loops fight for control. The one that is currently “stronger” is the Dominant Loop. The scary part is that you can’t always see the shift happening until it’s too late. The system might look like it’s growing (Reinforcing dominance) right up until the moment it hits a wall (Balancing dominance).
The Classic Example: S-Shaped Growth
The best way to see loop dominance in action is the S-Curve (Sigmoid Curve), which describes almost everything in nature and business, from the spread of a virus to the sales of a new iPhone.
Phase 1: Reinforcing Dominance (The Rocket Ship) 🚀
At the start, the system is driven by a Reinforcing Loop.
- Behavior: Exponential growth. The curve swoops upward.
- The Story: “I tell two friends, they tell two friends.” The more people who know, the faster the word spreads.
- Dominance: The R-loop is dominant because there is plenty of “potential market” left. The limit is far away, so it doesn’t push back yet.
Phase 2: The Shift (The Inflection Point)
As the system grows, it starts to consume its resources (potential customers, available space, nutrients). The Balancing Loop—which was weak before—starts to get stronger.
- The Story: There are fewer people left to tell. It becomes harder to find a new customer.
- Dominance: The tug-of-war is even. The growth rate hits its peak and starts to slow down.
Phase 3: Balancing Dominance (The Plateau)
Finally, the system hits its limit.
- Behavior: The curve flattens out. The goal has been reached (saturation).
- The Story: Everyone who wants an iPhone already has one. Sales only happen when an old phone breaks (replacement).
- Dominance: The Balancing Loop is now fully in control. No matter how much money you spend on ads (trying to trigger the R-loop), the B-loop (market saturation) wins.
Why Managers Miss the Shift
The concept of Loop Dominance explains why so many successful companies fail.
Managers often fall in love with the Reinforcing Phase. They build their entire strategy, budget, and culture around the assumption that “Growth is Normal.” They look at the chart and see a line going up.
However, a Systems Thinker looks at the same chart and asks: “What is the limiting factor?” They know that the Balancing Loop is lurking in the background, waiting to take over.
- If you don’t spot the shift in dominance, you will keep pushing the gas pedal (spending money on growth) when the engine is actually stalling (the market is full). This leads to wasted resources and panicked decision-making.
How to Identify the Dominant Loop
You can tell which loop is in control by looking at the Behavior Over Time Graph (the shape of the line).
| Behavior Shape | Dominant Loop | What it Means |
| Exponential Growth (J-Curve) | Reinforcing (R) | The system is feeding on itself. Resistance is weak. |
| Exponential Decay (Crashing) | Reinforcing (R) | The system is collapsing. The downward spiral is in control. |
| Slowing Growth / Flattening | Balancing (B) | The system is encountering a limit or resistance. |
| Oscillation (Waving up and down) | Balancing (B) + Delay | The system is trying to find balance but is overreacting due to delays. |
Conclusion
Loop Dominance is the advanced concept that turns a static map into a dynamic story. It teaches us that a system is not one fixed thing; it is a shifting battlefield. A startup is different from a mature corporation not just because of size, but because the Dominant Loop has shifted from Reinforcing growth to Balancing stability. By anticipating this shift, you can stop fighting the system and start adapting to its new reality.
