Wikipedia states that "Lean Software Development is a translation of lean manufacturing principles and practices to the software development domain."
Lean software development, to me, is best viewed as both the philosophical underpinning of Agile, and as the extension of a similar approach to the entire software 'production' chain, from conception, through approval, to deployment.
The main points that a developer or a program manager would find helpful are:
* System: Optimize the system, not each part separately
* Value: understand what creates value for your customer, and how your organization creates value
* Flow: Maximizing speed minimizes wastes
This one is hard to see at first. But delivering a functioning solution earlier is critical since:
- You are producing the solution since it has value to the customer. The sooner the customer uses a functioning system, the more time he gets the benefit for, so the higher his total benefit is. If the core systems would save the customer $100k a month, delivering a core system 3 months later just cost $300k
- The time it takes to initiate and approve a project counts as cost, too. That stack of 'waiting for approval' projects on the VP's desk is costing the organization, the same way that the queue of people waiting for service in the grocery store costs you time.
- The more 'outstanding' projects there are, the more multitasking people need to do. Multitasking is expensive and inefficient.
- The more time passes, the less knowledge is fresh. Knowledge is what software development is all about.
* Pull: Deliver value based on customer (or next-in-production-chain) needs
And the perfect bad example is when the test organization is months behind the developers in testing. The dev team might be code-complete, but the product won't be shipping for six more months...
Special thanks to Alan Shalloway and his Lean presentation. The errors, of course, are all mine.