The next lightweight model we will touch upon in this book is called Scrum, which, as of 2018, has been widely adopted outside the IT realm. It is not a method such as DSDM and can be better described as a framework. It uses the paradigm of a sports team (rugby, to be exact), where a group of people work together to achieve a goal. In the rugby game, a scrum drives the ball into the game. The scrum group consists of five to eight players who operate as a unit. In the IT world, it is a group of people who create business value through close cooperation and coordination.

In Rugby, each player has a unique position; they play both roles in attack and defense, and they work as a team to get the ball to the other side. It can be compared to a situation in IT, where the degree of success of a scrum team depends on the different disciplines within the team and how they work together and coordinate with each other.

The Rugby comparison originates from a 1986 article from the Harvard Business Review, The New Product Development Game, where the authors Takeuchi and Nonaka introduced the term scrum in the context of product development. They argued that it would bring more speed and flexibility, and they based it on case studies done in several industries, notably the automotive industries.

In the early 1990s, Ken Schwaber and Jeff Sutherland started using scrum techniques in their companies, and eventually in 1995, they presented a paper describing the Scrum framework at a software design conference.

Scrum sets out the following values:

• Commitment: The members must fully commit themselves to the project; it is not a part-time job.
• Focus: embers should focus on what needs to be done in each sprints.
• Openness (Transparency): People must keep each other well informed about progress and possible problems.
• Respect: Members must respect those with a different background and expertise and trust each other's good intent.
• Guts: Members must have the courage to say things, ask questions, and come up with new solutions.

Scrum works with multidisciplinary teams who prefer to work in one room so that consultation is easy. The team is supervised by a scrum master, who has a facilitating role. The product owner is the customer or a client, or a representative thereof. He or she specifies the desired results, usually in the form of user stories. These user stories are kept in a list, the product backlog, or the work stock. The product owner sorts the work stock for priority. The most important user stories are at the top.

In Scrum, you work in sprints or iterations. These usually last from about a week to a month, with a duration of two weeks as the most common. Sprints are timeboxed. In other words, it is certain in advance how long a Sprint will last for and when it will end. At the beginning of a sprint, the user stories for that Sprint are determined and recorded in the sprint backlog.

Sprints provide results that are as tangible as possible. This means that the software development will provide usable code, including integration, tests, and documentation, that is understandable for the customer or end user.

At the end of a sprint, a sprint review takes place, where the result is shown to the product owner. In addition, an evaluation takes place within the team.