The Lean Startup is most likely the best example of how to translate Lean into software development directly. This set of management tools uses nearly all the Lean tools identified in the famous texts of Lean, such as Toyota Way, Lean Thinking, and Toyota Production System. In fact there are so many similarities between the two people have accused the author of basically writing a book about Lean and not adding anything to the topic. I, personally, don’t agree with this as the portions about pivoting is definitely not part of the Lean framework and is novel capability he introduced.
Furthermore, he’s had to translate a great deal of the language from manufacturing or office settings into a development setting. While there are similarities there are differences between a piece of finished goods and a completed piece of code. This difference is that the code can be pushed to “production” servers and active for users, while the finished good has to be purchased by a customer, which still may take weeks to occur (if the production system is linked to purchase orders and directly to customers). To that end Reis pushed to make as many changes to production as quickly as possible – not without testing of course, but as soon as testing was completed the change went live. This is an extreme case of single piece flow. One change goes through testing and pushed live.
Pushing in the “Continuous Deployment” model of course causes a lot of issues if you don’t have robust testing. You need the testing to be fast but comprehensive. It’s impossible to do this from the beginning so over time the team has to develop more and more sophisticated tests based on how the team breaks the existing piece of software as they deploy changes. This is where Root Cause analysis plays a key role. Do a 5 Why’s analysis (ask why 5 times until you come to an underlying root cause) fix that problem so it never happens again. In the case where you cannot prevent the issue then you need to be automatically testing for the issue to fix it before you publish the change.
Agile has similar concepts in that they there are short cycles of development called “sprints” these sprints can last anywhere from a week to a month. At the end of each sprint the goal is to have a series of features that are deploy-able (including testing) that a customer would be willing to pay for. These pieces of work are broken down into something called a “minimum viable feature” which is smaller than a product but not so small that it wouldn’t completely work. For example, an MVF of WordPress would be the “publish button” initially it would need to convert all the text in the text editor and turn everything into a viewable website and create the URL associated with that article. Over time new features can be added like the auto-tweeting capability that exist now.
One common theme between both approaches is the concept of minimum viable product, which is a set of features that makes up the product. The difference between the two approaches in developing the MVP is that the Product owner does this in Agile, while the MVP is determined through a great deal of customer interaction in Lean Startup (Ideally the Product Owner is doing a similar activity for the customer but typically acts as a proxy).
There hasn’t been a lot of authors that have looked into combining these two approaches. There are a lot of similarities as they both emerged from the Lean philosophy, which means they should be fairly easy to combine into a larger framework. The only book I’m aware of that has even attempted to tackle this is the “Lean Mindset” by Tom and Mary Poppendieck. Even in this book though, they have decided to go with a 4 step approach that has more phases than what the Lean Startup recommends. They propose the stage gate to help determine minimum levels of details. I believe that this is because of the typical levels of bureaucracies in organizations, where a Project Management Organization will require adhering to some sort of phased gate approach. The Lean Startup uses Pivots as a way to manage projects that are failing, but not with the same level of rigor or structure as the approach the Poppendiek’s recommend. Instead, the Lean Startup approach recommends setting goals and targets for metrics (non-vanity like number of views) determining when to pivot. The timeline has to be long enough to get a clear view of what your customers actually want.