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Toyota started its journey with lean product development at Toyoda Loom Works (see History of Toyota), rather than the lean manufacturing that became famous through the book "The Machine that changed the world".
When Toyota started developing cars, there was a difference between its context in Japan and its competitors in the USA. Toyota had few educated engineers and little prior experience. Car companies in US had the benefit of engineering schools and a well-educated work force in the cities. To tackle this shortfall in knowledge and experience, Toyota conducted an incremental approach to development that built on this knowledge and became the basis of the lean systems Toyota uses today.
Allen Ward studied Toyota's lean product development system, and found parallels with the US airplane industry. For instance, the Wright brothers' method of constructing their airplane became one of the legacies they passed on to the aviation industry. This approach enabled the USA to create one of World War 2's most successful fighter planes from scratch, in just six months. After the war Toyota incorporated many of the airline industry's findings into its own product development methodology.
While some basic principles and guidelines are applicable across lean product development and lean production, such as waste reduction, many applications of lean process for development have focused more on the production approach.
The purpose of production, is to manufacture products reliably within margins of control. The flow of value is physically evident and the link between cause and effect is easy to see. For example, feedback on adjusting the speed of production is immediately realized in an increase or decrease in rejected items. Any decisions made must be based on best practice.
The purpose of product development, on the other hand, is to design new products that improve the life of customers. This is a complex space where the flow of value can only be discerned at an abstract level and cause and effect might be separated by time and space. For example, feedback on the decision to design a certain feature will not be received until the product has been built and is in the hands of the customer. This means that decisions are made on short-cycle experimentation, prototyping, set-based design, and emergent practice. A premium is placed on creating reusable knowledge and reducing risk at handover points.
An essential point about these differences is summarized in the advice Jim Womack gives Harley Davidson: "Don't try to bring lean manufacturing upstream to product development. The application of Lean in product development and manufacturing are different. Some aspects may look similar, but they are not! Be leary of an expert with experience in lean manufacturing that claims to know product development" 
The most common high level concepts associated with lean product development are:
The following results have been claimed for lean product development:
In the year 2000, Toyota launched 14 new products which is more than whole of GM. At that point, Toyota had just 70,000 employees, while GM had more than five times as many (360,000).
Researchers divide product development projects accordingly to their need driver:
For example: In the 1990s the mobile phone was a Wanted product, it was on the leading edge of technology. Today it is regarded as a Needed product, it is common in the market and there is enough knowledge in the public domain so that even small companies can make a good mobile phone.
Product development methods can be classified according to whether they are focused on handling stable or unstable conditions. Lean product development is a dynamic method of product development that handles unstable conditions.
Putting this together gives us an understanding of how why it is important to understand both need driver and if your projects are deemed short or long compared to market changes and have a product development approach that addresses the situation you face.
|Wanted||moderately non-stable||moderately non-stable||non-stable|