4 P-Model by Jeffrey Liker

Introduction: 4 P-Model

The 4 P-Model, created by Jeffrey K. Liker in his book The Toyota Way, is a framework that explains how Lean thinking should be understood and applied. It goes beyond tools and methods, showing that Lean success depends on philosophy, people, partners, and problem solving.

Background

The model was developed to make the Toyota Production System easier to understand for organisations worldwide. Instead of focusing only on efficiency tools, it highlights the importance of culture, leadership, and relationships. The 4 P-Model provides a balanced view of what makes Lean sustainable.

Key Elements / Features

The four Ps are:

1. Philosophy (Long Term) – Focus on long-term vision and continuous improvement instead of short-term results.
2. People (Process Waste) – Reduce waste using the 3 MU (Muda, Mura, Muri) while also developing employees.
3. Partners (People and Partners) – Build trust and collaboration with suppliers to improve the whole supply chain.
4. Problem Solving – Use Lean tools like Kaizen, Six Sigma, and the 5 Whys to solve problems at the root cause.

Applications / Examples

Organisations apply the 4 P-Model as a guide for Lean transformation. For example, a company may define its long-term philosophy, train staff to spot waste, involve suppliers in improvement, and use Kaizen events to solve recurring issues.

Relevance / Impact

The 4 P-Model is valuable because it shows that Lean is not just about tools, but about mindset and culture. By integrating philosophy, people, partners, and problem solving, organisations can achieve lasting improvement and resilience.

See also

• The 14 Principles of the Toyota Way
• 3 MU
• Kaizen
• 5 Whys