One thing I often hear when I talk about creating effective service delivery or development and mentions its root in the Toyota Production System is that it would be a bad thing to use insights from manufacturing in other domains. There seems to be a fear that using ways of thinking from a production system automatically will make one treat everything and everyone as things to produce or cogs in a machinery. Seldom that criticism comes from people who has knowledge of what the thinking from Toyota actually says, though.
While it is true that some of the techniques that Toyota invented in the 50s and the 60s are only applicable in a manufacturing context, most of them are about general human concepts such as leadership, human collaboration, improvement of quality, and last but not least: flow.
Value is about meeting human needs. A value stream is what we call the organisation around the sum of all things that is done to capture and understand that need, and to finally meet it with a delivery of some sort. A smooth and fast slow is what we aim for since that would increase the value output per time unit.
Henry Ford optimized for flow when he designed the Highland Park factory that opened in 1912. Frederick Winslow Taylor optimized for flow when he wrote The Principles of Scientific Management in 1911. But even if the methods these persons enforced to increase flow such as predefined work divided into repetitive moments isn't suitable in any context outside of manufacturing (and maybe not even there), the aim for a steady output of value was not wrong but something that increased the income so much that they could pay the workers way more than the workers in other factories.
Flow has always been a core factor in successful service delivery: how do we handle a huge variation in demand and still provide adequate value to recipients? And what is true for service delivery tends to be true for product and service development as well. The Wright brothers solved the problems of creating a propelled heavier-than-air flying machine by a steady series of many experiments, and so has effective development work been conducted ever since, including within Toyota.
Lean thinking has from the beginning been about general concepts such as mathematical facts about collaboration systems in general and psychological facts about the human nature. The two pillars of lean is the continuous improvement of the flow, and respect for the fact that we people are as we are. William Deming's system of profound knowledge is based on the same two fundaments: flow (understanding systems and variation), and psychology (understanding knowledge and the human mind and behaviour).
If you are interested in general lean concepts I recommend This Is Lean, The Machine That Changed The World, Gemba Walks, Lean Thinking, and Toyota Kata. If you are interested in lean service delivery I recommend that you look at Vanguard by John Seddon. And if you want to implement lean thinking in knowledge work, I recommend that you check out Lean Software Development by Mary and Tom Poppendieck. For a thorough walkthrough of several economic principles that apply to product development using lean thinking, I recommend Flow by Don Reinertsen.
It s all about flow, not about factories and manufacturing.