Lean is a method for organizing any large groups of individuals to meet a complex end. Lean concepts were first formulated in the manufacturing function, and these same concepts have since been applied to business areas such as finance, sales, internal administration and product development.

Any product development group that includes more than 10 people faces coordination challenges. In product development, the actions of any one person on the team can affect the design decisions of anyone and everyone else. 

The first step to Lean product development is to stabilize your existing product development processes. The best route to stabilization is to have standardized work processes. All repeatable work processes should have clear work instructions that are followed on a consistent basis. These instructions should also include the time it should take to execute the task at hand.

After the process has been stabilized,  your organization is ready to implement a Lean product development process. Lean product development has four main elements:

• Flow is the notion that the work progresses from each step to the next without stopping. Consider an automotive factory. The car travels on a moving production line from one work station to another without stopping. Everyone understands the work that they must do to add value to the work product as it moves down the production line.  Processes that flow have been shown to be more efficient and to eliminate waste. In your product development "factory," the "parts" might include customer requirements, product specs, pans, schedules and drawings. In a Lean process, product development work-in-process moves from one station to another without stopping, just as on the factory floor. 
  
  
• Pace is the notion that everything works to a rhythm. To regulate the product development heartbeat, each of the contributing activities must have its own rhythm. The car factory also operates best when it has a rhythm. Every 56 seconds, a car comes down the production line, and you know that you have to do a certain set of tasks in that time. Finding a regular rhythm in your activities is an important means of creating an efficient organization. The first step to achieving a regular rhythm is to decide on the frequency of new product releases or revisions. Then, design your end-to-end product development process so that your system can deliver that product at the rhythm that the market demands. For example, if customers expect a new and improved cellphone every year then a cell phone developer needs to design its entire product development process around that rhythm.
  
  
• Pull is the principle that work is initiated by the customer. Customers might be either internal or external. In a Lean organization the entire chain of product development activities, from gathering market requirements to defining products, to the detailed design, to the hand-off to manufacturing, is conceived in terms of a supplier-customer relationship. Each contributor is the supplier to someone else downstream and each person or group downstream is a customer to the party upstream. The group downstream is the initiator in each of step of this chain. The downstream group requests goods and services from the group upstream.

• Level refers to the Lean principle that resources should move from task to task easily and quickly. There is a "leveling" of the effort so that work-in-process does not accumulate in any one place. Without leveling, bottlenecks occur because some people will accomplish a task faster than others. To achieve leveling, management must be aware of each person's capacity. Then the company should invest in cross-training its employees so that they have a range of skills. Then they can move from one task to another to ensure that no one’s work is much greater than anyone else’s.

Lean concepts on the factory floor focus on eliminating wasted materials, resolving bottlenecks and reducing non-value-added activities. At the highest level, Lean product development is no different. It is also oriented toward efficiency but the means to this end is to establish a a cycle of learning in your design process. Product development is about eliminating unknowns. Lean product development enables organizations to create rapid learning cycles that speed winning new products to market.