The lean gap: A review of lean approaches to large-scale software systems development
Lean approaches to product development (LPD) have had a strong influence on many industries and in recent years there have been many proponents for lean in software development as it can support the increasing industry need of scaling agile software development. With it's roots in industrial manufacturing and, later, industrial product development, it would seem natural that LPD would adapt well to large-scale development projects of increasingly software-intensive products, such as in the automotive industry. However, it is not clear what kind of experience and results have been reported on the actual use of lean principles and practices in software development for such large-scale industrial contexts. This was the motivation for this study as the context was an ongoing industry process improvement project at Volvo Car Corporation and Volvo Truck Corporation. The objectives of this study are to identify and classify state of the art in large-scale software development influenced by LPD approaches and use this established knowledge to support industrial partners in decisions on a software process improvement (SPI) project, and to reveal research gaps and proposed extensions to LPD in relation to its well-known principles and practices. For locating relevant state of the art we conducted a systematic mapping study, and the industrial applicability and relevance of results and said extensions to LPD were further analyzed in the context of an actual, industrial case. A total of 10,230 papers were found in database searches, of which 38 papers were found relevant. Of these, only 42 percent clearly addressed large-scale development. Furthermore, a majority of papers (76 percent) were non-empirical and many lacked information about study design, context and/or limitations. Most of the identified results focused on eliminating waste and creating flow in the software development process, but there was a lack of results for other LPD principles and practices. Overall, it can be concluded that research in the much hyped field of lean software development is in its nascent state when it comes to large scale development. There is very little support available for practitioners who want to apply lean approaches for improving large-scale software development, especially when it comes to inter-departmental interactions during development. This paper explicitly maps the area, qualifies available research, and identifies gaps, as well as suggests extensions to lean principles relevant for large scale development of software intensive systems.