Scrum is an iterative incremental process of software development commonly used with agile software development. Despite the fact that "Scrum" is not an acronym, some companies implementing the process have been known to adhere to an all capital letter expression of the word, i.e. SCRUM. This may be due to one of Ken Schwaber's early papers capitalizing SCRUM in the title.[1]

Although Scrum was intended to be for management of software development projects, it can be used in running software maintenance teams, or as a program management approach.

Contents

History

In 1986, Hirotaka Takeuchi and Ikujiro Nonaka described a new holistic approach which increases speed and flexibility in commercial new product development:[2] They compare this new holistic approach, in which the phases strongly overlap and the whole process is performed by one cross-functional team across the different phases, to rugby, where the whole team "tries to go to the distance as a unit, passing the ball back and forth". The case studies come from the automotive, photo machine, computer and printer industries.

In 1991, DeGrace and Stahl, in Wicked Problems, Righteous Solutions[3] referred to this approach as Scrum, a rugby term mentioned in the article by Takeuchi and Nonaka. In the early 1990s, Ken Schwaber used an approach that led to Scrum at his company, Advanced Development Methods. At the same time, Jeff Sutherland developed a similar approach at Easel Corporation and was the first to call it Scrum.[4] In 1995 Sutherland and Schwaber jointly presented a paper describing Scrum at OOPSLA '95 in Austin, its first public appearance. Schwaber and Sutherland collaborated during the following years to merge the above writings, their experiences, and industry best practices into what is now known as Scrum. In 2001 Schwaber teamed up with Mike Beedle to write up the method in the book "Agile Software Development with SCRUM".

Characteristics of Scrum

Scrum is a process skeleton that includes a set of practices and predefined roles. The main roles in Scrum are the ScrumMaster who maintains the processes and works similar to a project manager, the Product Owner who represents the stakeholders, and the Team which includes the developers.

During each sprint, a 15-30 day period (length decided by the team), the team creates an increment of potentially shippable (usable) software. The set of features that go into each sprint come from the product backlog, which is a prioritized set of high level requirements of work to be done. Which backlog items go into the sprint is determined during the sprint planning meeting. During this meeting the Product Owner informs the team of the items in the product backlog that he wants completed. The team then determines how much of this they can commit to complete during the next sprint.[1] During the sprint, no one is able to change the sprint backlog, which means that the requirements are frozen for a sprint.

There are several implementations of systems for managing the Scrum process which range from yellow stickers and white-boards to software packages. One of Scrum's biggest advantages is that it is very easy to learn and requires little effort to start using.

Scrum roles

Several roles are defined in Scrum; these are divided into two groups; pigs and chickens, based on a joke about a pig and a chicken.^[1]

A pig and a chicken are walking down a road. The chicken looks at the pig and says, "Hey, why don't we open a restaurant?" The pig looks back at the chicken and says, "Good idea, what do you want to call it?" The chicken thinks about it and says, "Why don't we call it 'Ham and Eggs'?" "I don't think so," says the pig, "I'd be committed but you'd only be involved."

So the pigs are committed to building software regularly and frequently, while everyone else is a chicken: interested in the project but really irrelevant because if it fails they're not a pig, that is they weren't the ones that committed to doing it. The needs, desires, ideas and influences of the chicken roles are taken into account, but not in any way letting it affect or distort or get in the way of the actual Scrum project.

"Pig" roles

Pigs are the ones committed to the project and the Scrum process; they are the ones with "their bacon on the line."

Product Owner

The Product Owner represents the voice of the customer. They ensure that the Scrum Team works with the right things from a business perspective. The Product Owner writes User Stories, prioritizes them, then places them in the Product Backlog.

ScrumMaster (or Facilitator)

Scrum is facilitated by a ScrumMaster, whose primary job is to remove impediments to the ability of the team to deliver the sprint goal. The ScrumMaster is not the leader of the team (as they are self-organizing) but acts as a buffer between the team and any distracting influences. The ScrumMaster ensures that the Scrum process is used as intended. The ScrumMaster is the enforcer of rules.

Team

The team has the responsibility to deliver the product. A small team of 5-9 people with cross-functional skills to do the actual work (designer, developer etc.).

"Chicken" roles

Chicken roles are not part of the actual Scrum process, but must be taken into account. An important aspect of an Agile approach is the practice of involving users, business and stakeholders into part of the process. It is important for these people to be engaged and provide feedback into the outputs for review and planning of each sprint.

Users

The software is being built for someone! If software is not used - much like 'the tree falling in a forest' riddle - was it ever written?

Stakeholders (Customers, Vendors)

The people that will enable the project and for whom the project will produce the agreed upon benefit(s) which justify it. They are only directly involved in the process at sprint reviews.

Managers

People that will set up the environment for the product development organizations.

The Scrum meeting

Each day during the sprint, a project status meeting occurs. This is called a scrum or "the daily standup". The scrum has specific guidelines:

• The meeting starts precisely on time. Often there are team-decided punishments for tardiness (e.g. money, push-ups, hanging a rubber chicken around your neck)
• All are welcome, but only "pigs" may speak
• The meeting is timeboxed at 15 minutes regardless of the team's size.
• All attendees should stand (it helps to keep meeting short)
• The meeting should happen at the same location and same time every day

During the meeting, each team member answers three questions:^[1]

• What have you done since yesterday?
• What are you planning to do by today?
• Do you have any problems preventing you from accomplishing your goal? (It is the role of the ScrumMaster to remember these impediments.)

At the end of a sprint cycle (every 15-30 days) a sprint retrospective is held, at which all team members reflect about the past sprint. The purpose of the retrospective is to make continuous process improvement. This meeting is timeboxed at four hours. Two main questions are asked in the sprint retrospective:^[1]

• What went well during the sprint?
• What could be improved in the next sprint?

Scrum enables the creation of self-organizing teams by encouraging co-location of all team members, and verbal communication across all team members and disciplines that are involved in the project.

A key principle of Scrum is its recognition that during a project the customers can change their minds about what they want and need (often called requirements churn), and that unpredicted challenges cannot be easily addressed in a traditional predictive or planned manner. As such, Scrum adopts an empirical approach – accepting that the problem cannot be fully understood or defined, focusing instead on maximizing the team's ability to deliver quickly and respond to emerging requirements.

Documents

Product backlog

The product backlog is a high-level document for the entire project. It contains broad descriptions of all required features, wish-list items, etc. It is the "What" that will be built. It is open and editable by anyone. It contains rough estimates, usually in days. This estimate helps the Product Owner to gauge the timeline and, to a limited extent, priority (e.g. if "add spellcheck" feature is estimated at 3 days vs 3 months, that may affect the Product Owner's desire).

Sprint backlog

The sprint backlog is a greatly detailed document containing information about how the team is going to implement the requirements for the upcoming sprint. Tasks are broken down into hours with no task being more than 16 hours. If a task is greater than 16 hours, it should be broken down further. Tasks on the sprint backlog are never assigned, rather tasks are signed-up for by the team members as they like.

Burn down

The burn down chart is a publicly displayed chart showing the number of tasks remaining for the current sprint or the number of items on the sprint backlog. It should not be confused with an earned value chart. A burn down chart could be flat for most of the period covered by a sprint and yet the project could still be on schedule.

Adaptive project management

Following are some general practices of Scrum:

• Customers become a part of the development team. (i.e. the customer must be genuinely interested in the output.)
• Like all other forms of agile software processes, Scrum has frequent intermediate deliveries with working functionality. This enables the customer to get working software earlier and enables the project to change its requirements according to changing needs.
• Frequent risk and mitigation plans developed by the development team itself. – Risk Mitigation, Monitoring and Management (risk analysis) at every stage and with commitment.
• Transparency in planning and module development – Let everyone know who is accountable for what and by when.
• Frequent stakeholder meetings to monitor progress – Balanced (Delivery, Customer, Employee, Process) Dashboard updates – Stakeholders' update – You have to have Advance Warning Mechanism, i.e. visibility to potential slippage / deviation ahead of time.
• No problems are swept under the carpet. No one is penalized for recognizing or describing any unforeseen problem.
• Workplaces and working hours must be energized. – "Working more hours" does not necessarily mean "producing more output."

Scrum terminology

The following terminology is used in Scrum^[1]:

Roles

Product Owner 

The person responsible for maintaining the Product Backlog by representing the interests of the stakeholders.

ScrumMaster 

The person responsible for the Scrum process, making sure it is used correctly and maximizes it benefits.

Team 

A cross-functional group of people responsible for managing itself to develop the product.

Scrum Team

Product Owner, ScrumMaster and Team

Artifacts

Sprint Burn Down Chart 

Daily progress for a Sprint over the sprint's length.

Product Backlog 

A prioritized list of high level requirements.

Sprint Backlog 

A list of tasks to be completed during the sprint.

Others

Sprint 

A time period (typically between 2 weeks and 1 month) in which development occurs on a set of backlog items that the Team has committed to.

Sashimi 

A slice of the whole equivalent in content to all other slices of the whole. For the Daily Scrum, the slice of sashimi is a report that something is done.

Extended usage of Scrum

Though Scrum was originally applied to software development only, it can also be successfully used in other industries. Now Scrum is often viewed as an iterative, incremental process for developing any product or managing any work.

Scrum applied to product development

Scrum as applied to product development was first referred to in "The New New Product Development Game" (Harvard Business Review 86116:137-146, 1986) and later elaborated in "The Knowledge Creating Company" both by Ikujiro Nonaka and Hirotaka Takeuchi (Oxford University Press, 1995). Today there are records of Scrum used to produce financial products, Internet products, and medical products by ADM.

Scrum as a marketing project management methodology

As marketing is often executed in project-based manner, a lot of generic project management principles apply to marketing. Marketing can be also optimized similar to project management techniques. Scrum approach to marketing is believed to be helpful for overcoming problems experienced by marketing executives. Short and regular meetings are important for small marketing teams, as every member of a team has to know what the others are working on and what direction the whole team is moving in. Scrum in marketing makes it possible to:

• See possible problems at early stages and allows coping with them quicker and with minimal losses. According to the key principle of Scrum “no problems are swept under the carpet”, every team member is encouraged to describe the difficulties he is experiencing, as this might influence the work of the whole group.
• Reduce financial risk. With the beginning of every sprint period, the business owner can change any of the marketing project parameters without penalty, including increasing investments to enlarge consumers’ quantity, reducing investments until unknowns are mitigated, or financing other initiatives.
• Make marketing planning flexible. Short-term marketing plans based on sprints can be much more effective. Marketing managers get an opportunity to switch from one promotion method to another, if the first one proved to be unsuccessful during the sprint period. It also becomes easier to clarify due dates of every small, but important, task to each member of a team.
• Involve clients in various ways.

There’s also a tendency to execute Scrum in marketing with the help of Enterprise 2.0 technologies and Project management 2.0 tools.

See also

• Kaizen
• List of software development philosophies
• User story
• Cowboy coding

Other Agile methods

• Dynamic System Development Method
• Feature Driven Development
• Extreme programming (XP)
• Software Development Rhythms

Supporting tools

• Teamwork (software)
• Agilo for Scrum Open Source Tool
• Burn down chart

References

External links

• Scrum in five minutes
• Scrum Alliance
• Agile Alliance's Scrum library
• (PDF) Rising, L., Janoff, N.S. (2000). The Scrum Software Development Process for Small Teams Retrieved March 15, 2007
• (PDF) Schwaber, K. Advanced Development Methods. SCRUM Development Process Retrieved August 15, 2006
• (video) Jeff Sutherland in Scrum Tuning: Lessons learned from Scrum implementation at Google Retrieved 2007-12-15
• (video) Ken Schwaber in Scrum et al. Retrieved 2008-01-19