According to a National Center for Manufacturing Sciences report, Toyota product development projects can take half the time of US equivalents, with four times their productivity (150 product engineers utilised by Toyota per car programme versus 600 for twice as long at Chrysler).
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As with implementing the Toyota production system, a more precise understanding of development practices doesn’t necessarily help to improve the efficiency of engineering projects for a number of reasons. First, it is not a collection of best practices which can be implemented piecemeal, but a system. Furthermore, a clearer understanding of the system also shines a different light on the practices themselves, and, in many cases, changes their intended purpose. As such, many of the Toyota practices only make sense in the light of the overall system.