Scrum is a framework for developing, delivering, and sustaining complex products. This Guidecontains the definition of Scrum. This definition consists of Scrum’s roles, events, artifacts, andthe rules that bind them together. Ken Schwaber and Jeff Sutherland developed Scrum; theScrum Guide is written and provided by them. Together, they stand behind the Scrum Guide.
Scrum (n): A framework within which people can address complex adaptive problems, whileproductively and creatively delivering products of the highest possible value.
Scrum is:
Scrum is a process framework that has been used to manage work on complex products sincethe early 1990s. Scrum is not a process, technique, or definitive method. Rather, it is aframework within which you can employ various processes and techniques. Scrum makes clearthe relative efficacy of your product management and work techniques so that you cancontinuously improve the product, the team, and the working environment.
The Scrum framework consists of Scrum Teams and their associated roles, events, artifacts, andrules. Each component within the framework serves a specific purpose and is essential toScrum’s success and usage.
The rules of Scrum bind together the roles, events, and artifacts, governing the relationships andinteraction between them. The rules of Scrum are described throughout the body of thisdocument.
Specific tactics for using the Scrum framework vary and are described elsewhere.
Scrum was initially developed for managing and developing products. Starting in the early 1990s, Scrum has been used extensively, worldwide, to:
Scrum has been used to develop software, hardware, embedded software, networks ofinteracting function, autonomous vehicles, schools, government, marketing, managing theoperation of organizations and almost everything we use in our daily lives, as individuals andsocieties.
As technology, market, and environmental complexities and their interactions have rapidlyincreased, Scrum’s utility in dealing with complexity is proven daily.
Scrum proved especially effective in iterative and incremental knowledge transfer. Scrum is nowwidely used for products, services, and the management of the parent organization.
The essence of Scrum is a small team of people. The individual team is highly flexible andadaptive. These strengths continue operating in single, several, many, and networks of teamsthat develop, release, operate and sustain the work and work products of thousands of people.They collaborate and interoperate through sophisticated development architectures and targetrelease environments.
When the words “develop” and “development” are used in the Scrum Guide, they refer tocomplex work, such as those types identified above.
Scrum is founded on empirical process control theory, or empiricism. Empiricism asserts thatknowledge comes from experience and making decisions based on what is known. Scrumemploys an iterative, incremental approach to optimize predictability and control risk.
Three pillars uphold every implementation of empirical process control: transparency,inspection, and adaptation.
Transparency
Significant aspects of the process must be visible to those responsible for the outcome.Transparency requires those aspects be defined by a common standard so observers share acommon understanding of what is being seen.
For example
Inspection
Scrum users must frequently inspect Scrum artifacts and progress toward a Sprint Goal to detectundesirable variances. Their inspection should not be so frequent that inspection gets in the wayof the work. Inspections are most beneficial when diligently performed by skilled inspectors atthe point of work.
Adaptation
If an inspector determines that one or more aspects of a process deviate outside acceptablelimits, and that the resulting product will be unacceptable, the process or the material beingprocessed must be adjusted. An adjustment must be made as soon as possible to minimizefurther deviation.
Scrum prescribes four formal events for inspection and adaptation, as described in the Scrum Events section of this document:
When the values of commitment, courage, focus, openness and respect are embodied and livedby the Scrum Team, the Scrum pillars of transparency, inspection, and adaptation come to lifeand build trust for everyone. The Scrum Team members learn and explore those values as theywork with the Scrum roles, events, and artifacts.
Successful use of Scrum depends on people becoming more proficient in living these five values.People personally commit to achieving the goals of the Scrum Team. The Scrum Team membershave courage to do the right thing and work on tough problems. Everyone focuses on the workof the Sprint and the goals of the Scrum Team. The Scrum Team and its stakeholders agree to beopen about all the work and the challenges with performing the work. Scrum Team membersrespect each other to be capable, independent people.
The Scrum Team consists of a Product Owner, the Development Team, and a Scrum Master.Scrum Teams are self-organizing and cross-functional. Self-organizing teams choose how best toaccomplish their work, rather than being directed by others outside the team. Cross-functionalteams have all competencies needed to accomplish the work without depending on others notpart of the team. The team model in Scrum is designed to optimize flexibility, creativity, andproductivity. The Scrum Team has proven itself to be increasingly effective for all the earlierstated uses, and any complex work.
Scrum Teams deliver products iteratively and incrementally, maximizing opportunities forfeedback. Incremental deliveries of “Done” product ensure a potentially useful version ofworking product is always available.
The Product Owner
The Product Owner is responsible for maximizing the value of the product resulting from workof the Development Team. How this is done may vary widely across organizations, Scrum Teams,and individuals.
The Product Owner is the sole person responsible for managing the Product Backlog. ProductBacklog management includes:
The Product Owner may do the above work, or have the Development Team do it. However, theProduct Owner remains accountable.
The Product Owner is one person, not a committee. The Product Owner may represent thedesires of a committee in the Product Backlog, but those wanting to change a Product Backlogitem’s priority must address the Product Owner.
For the Product Owner to succeed, the entire organization must respect his or her decisions. TheProduct Owner’s decisions are visible in the content and ordering of the Product Backlog. Noone can force the Development Team to work from a different set of requirements.
The Development Team
The Development Team consists of professionals who do the work of delivering a potentiallyreleasable Increment of “Done” product at the end of each Sprint. A “Done” increment isrequired at the Sprint Review. Only members of the Development Team create the Increment.
Development Teams are structured and empowered by the organization to organize andmanage their own work. The resulting synergy optimizes the Development Team’s overallefficiency and effectiveness.
Development Teams have the following characteristics:
Development Team Size
Optimal Development Team size is small enough to remain nimble and large enough tocomplete significant work within a Sprint. Fewer than three Development Team membersdecrease interaction and results in smaller productivity gains. Smaller Development Teams mayencounter skill constraints during the Sprint, causing the Development Team to be unable todeliver a potentially releasable Increment. Having more than nine members requires too muchcoordination. Large Development Teams generate too much complexity for an empirical processto be useful. The Product Owner and Scrum Master roles are not included in this count unlessthey are also executing the work of the Sprint Backlog.
Scrum Master
The Scrum Master is responsible for promoting and supporting Scrum as defined in the ScrumGuide. Scrum Masters do this by helping everyone understand Scrum theory, practices, rules,and values.
The Scrum Master is a servant-leader for the Scrum Team. The Scrum Master helps thoseoutside the Scrum Team understand which of their interactions with the Scrum Team are helpfuland which aren’t. The Scrum Master helps everyone change these interactions to maximize thevalue created by the Scrum Team.
Scrum Master Service to the Product Owner
The Scrum Master serves the Product Owner in several ways, including:
Scrum Master Service to the Development Team
The Scrum Master serves the Development Team in several ways, including:
Scrum Master Service to the Organization
The Scrum Master serves the organization in several ways, including:
Prescribed events are used in Scrum to create regularity and to minimize the need for meetingsnot defined in Scrum. All events are time-boxed events, such that every event has a maximumduration. Once a Sprint begins, its duration is fixed and cannot be shortened or lengthened. Theremaining events may end whenever the purpose of the event is achieved, ensuring anappropriate amount of time is spent without allowing waste in the process.
Other than the Sprint itself, which is a container for all other events, each event in Scrum is aformal opportunity to inspect and adapt something. These events are specifically designed toenable critical transparency and inspection. Failure to include any of these events results inreduced transparency and is a lost opportunity to inspect and adapt.
The Sprint
The heart of Scrum is a Sprint, a time-box of one month or less during which a “Done”, useable,and potentially releasable product Increment is created. Sprints have consistent durationsthroughout a development effort. A new Sprint starts immediately after the conclusion of theprevious Sprint.
Sprints contain and consist of the Sprint Planning, Daily Scrums, the development work, theSprint Review, and the Sprint Retrospective.
During the Sprint:
Each Sprint may be considered a project with no more than a one-month horizon. Like projects,Sprints are used to accomplish something. Each Sprint has a goal of what is to be built, a designand flexible plan that will guide building it, the work, and the resultant product increment.
Sprints are limited to one calendar month. When a Sprint’s horizon is too long the definition ofwhat is being built may change, complexity may rise, and risk may increase. Sprints enablepredictability by ensuring inspection and adaptation of progress toward a Sprint Goal at leastevery calendar month. Sprints also limit risk to one calendar month of cost.
Cancelling a Sprint
A Sprint can be cancelled before the Sprint time-box is over. Only the Product Owner has theauthority to cancel the Sprint, although he or she may do so under influence from thestakeholders, the Development Team, or the Scrum Master.
A Sprint would be cancelled if the Sprint Goal becomes obsolete. This might occur if thecompany changes direction or if market or technology conditions change. In general, a Sprintshould be cancelled if it no longer makes sense given the circumstances. But, due to the shortduration of Sprints, cancellation rarely makes sense.
When a Sprint is cancelled, any completed and “Done” Product Backlog items are reviewed. Ifpart of the work is potentially releasable, the Product Owner typically accepts it. All incompleteProduct Backlog Items are re-estimated and put back on the Product Backlog. The work done onthem depreciates quickly and must be frequently re-estimated.
Sprint cancellations consume resources, since everyone regroups in another Sprint Planning tostart another Sprint. Sprint cancellations are often traumatic to the Scrum Team, and are veryuncommon.
Sprint Planning
The work to be performed in the Sprint is planned at the Sprint Planning. This plan is created bythe collaborative work of the entire Scrum Team.
Sprint Planning is time-boxed to a maximum of eight hours for a one-month Sprint. For shorterSprints, the event is usually shorter. The Scrum Master ensures that the event takes place andthat attendants understand its purpose. The Scrum Master teaches the Scrum Team to keep itwithin the time-box.
Sprint Planning answers the following:
Topic One: What can be done this Sprint?
The Development Team works to forecast the functionality that will be developed during theSprint. The Product Owner discusses the objective that the Sprint should achieve and theProduct Backlog items that, if completed in the Sprint, would achieve the Sprint Goal. The entireScrum Team collaborates on understanding the work of the Sprint.
The input to this meeting is the Product Backlog, the latest product Increment, projectedcapacity of the Development Team during the Sprint, and past performance of the DevelopmentTeam. The number of items selected from the Product Backlog for the Sprint is solely up to theDevelopment Team. Only the Development Team can assess what it can accomplish over theupcoming Sprint.
During Sprint Planning the Scrum Team also crafts a Sprint Goal. The Sprint Goal is an objectivethat will be met within the Sprint through the implementation of the Product Backlog, and itprovides guidance to the Development Team on why it is building the Increment.
Topic Two: How will the chosen work get done?
Having set the Sprint Goal and selected the Product Backlog items for the Sprint, theDevelopment Team decides how it will build this functionality into a “Done” product Incrementduring the Sprint. The Product Backlog items selected for this Sprint plus the plan for deliveringthem is called the Sprint Backlog.
The Development Team usually starts by designing the system and the work needed to convertthe Product Backlog into a working product Increment. Work may be of varying size, orestimated effort. However, enough work is planned during Sprint Planning for the DevelopmentTeam to forecast what it believes it can do in the upcoming Sprint. Work planned for the firstdays of the Sprint by the Development Team is decomposed by the end of this meeting, often tounits of one day or less. The Development Team self-organizes to undertake the work in theSprint Backlog, both during Sprint Planning and as needed throughout the Sprint.
The Product Owner can help to clarify the selected Product Backlog items and make trade-offs.If the Development Team determines it has too much or too little work, it may renegotiate theselected Product Backlog items with the Product Owner. The Development Team may also inviteother people to attend to provide technical or domain advice.
By the end of the Sprint Planning, the Development Team should be able to explain to theProduct Owner and Scrum Master how it intends to work as a self-organizing team toaccomplish the Sprint Goal and create the anticipated Increment.
Sprint Goal
The Sprint Goal is an objective set for the Sprint that can be met through the implementation ofProduct Backlog. It provides guidance to the Development Team on why it is building theIncrement. It is created during the Sprint Planning meeting. The Sprint Goal gives theDevelopment Team some flexibility regarding the functionality implemented within the Sprint.The selected Product Backlog items deliver one coherent function, which can be the Sprint Goal.The Sprint Goal can be any other coherence that causes the Development Team to worktogether rather than on separate initiatives.
As the Development Team works, it keeps the Sprint Goal in mind. In order to satisfy the SprintGoal, it implements functionality and technology. If the work turns out to be different than theDevelopment Team expected, they collaborate with the Product Owner to negotiate the scopeof Sprint Backlog within the Sprint.
Daily Scrum
The Daily Scrum is a 15-minute time-boxed event for the Development Team. The Daily Scrum isheld every day of the Sprint. At it, the Development Team plans work for the next 24 hours. Thisoptimizes team collaboration and performance by inspecting the work since the last Daily Scrumand forecasting upcoming Sprint work. The Daily Scrum is held at the same time and place eachday to reduce complexity.
The Development Team uses the Daily Scrum to inspect progress toward the Sprint Goal and toinspect how progress is trending toward completing the work in the Sprint Backlog. The DailyScrum optimizes the probability that the Development Team will meet the Sprint Goal. Everyday, the Development Team should understand how it intends to work together as a self-organizing team to accomplish the Sprint Goal and create the anticipated Increment by the endof the Sprint.
The structure of the meeting is set by the Development Team and can be conducted in differentways if it focuses on progress toward the Sprint Goal. Some Development Teams will usequestions, some will be more discussion based. Here is an example of what might be used:
The Development Team or team members often meet immediately after the Daily Scrum fordetailed discussions, or to adapt, or replan, the rest of the Sprint’s work.
The Scrum Master ensures that the Development Team has the meeting, but the DevelopmentTeam is responsible for conducting the Daily Scrum. The Scrum Master teaches theDevelopment Team to keep the Daily Scrum within the 15-minute time-box.
The Daily Scrum is an internal meeting for the Development Team. If others are present, theScrum Master ensures that they do not disrupt the meeting.
Daily Scrums improve communications, eliminate other meetings, identify impediments todevelopment for removal, highlight and promote quick decision-making, and improve theDevelopment Team’s level of knowledge. This is a key inspect and adapt meeting.
Sprint Review
A Sprint Review is held at the end of the Sprint to inspect the Increment and adapt the ProductBacklog if needed. During the Sprint Review, the Scrum Team and stakeholders collaborateabout what was done in the Sprint. Based on that and any changes to the Product Backlogduring the Sprint, attendees collaborate on the next things that could be done to optimize value.This is an informal meeting, not a status meeting, and the presentation of the Increment isintended to elicit feedback and foster collaboration.
This is at most a four-hour meeting for one-month Sprints. For shorter Sprints, the event isusually shorter. The Scrum Master ensures that the event takes place and that attendeesunderstand its purpose. The Scrum Master teaches everyone involved to keep it within the time-box.
The Sprint Review includes the following elements:
The result of the Sprint Review is a revised Product Backlog that defines the probable ProductBacklog items for the next Sprint. The Product Backlog may also be adjusted overall to meet newopportunities.
Sprint Retrospective
The Sprint Retrospective is an opportunity for the Scrum Team to inspect itself and create a planfor improvements to be enacted during the next Sprint.
The Sprint Retrospective occurs after the Sprint Review and prior to the next Sprint Planning.This is at most a three-hour meeting for one-month Sprints. For shorter Sprints, the event isusually shorter. The Scrum Master ensures that the event takes place and that attendantsunderstand its purpose.
The Scrum Master ensures that the meeting is positive and productive. The Scrum Masterteaches all to keep it within the time-box. The Scrum Master participates as a peer teammember in the meeting from the accountability over the Scrum process.
The purpose of the Sprint Retrospective is to:
The Scrum Master encourages the Scrum Team to improve, within the Scrum processframework, its development process and practices to make it more effective and enjoyable forthe next Sprint. During each Sprint Retrospective, the Scrum Team plans ways to increaseproduct quality by improving work processes or adapting the definition of “Done”, if appropriateand not in conflict with product or organizational standards.
By the end of the Sprint Retrospective, the Scrum Team should have identified improvementsthat it will implement in the next Sprint. Implementing these improvements in the next Sprint isthe adaptation to the inspection of the Scrum Team itself. Although improvements may beimplemented at any time, the Sprint Retrospective provides a formal opportunity to focus oninspection and adaptation.
Scrum’s artifacts represent work or value to provide transparency and opportunities forinspection and adaptation. Artifacts defined by Scrum are specifically designed to maximizetransparency of key information so that everybody has the same understanding of the artifact.
Product Backlog
The Product Backlog is an ordered list of everything that is known to be needed in the product.It is the single source of requirements for any changes to be made to the product. The ProductOwner is responsible for the Product Backlog, including its content, availability, and ordering.
A Product Backlog is never complete. The earliest development of it lays out the initially knownand best-understood requirements. The Product Backlog evolves as the product and theenvironment in which it will be used evolves. The Product Backlog is dynamic; it constantlychanges to identify what the product needs to be appropriate, competitive, and useful. If aproduct exists, its Product Backlog also exists.
The Product Backlog lists all features, functions, requirements, enhancements, and fixes thatconstitute the changes to be made to the product in future releases. Product Backlog items havethe attributes of a description, order, estimate, and value. Product Backlog items often includetest descriptions that will prove its completeness when “Done.”
As a product is used and gains value, and the marketplace provides feedback, the ProductBacklog becomes a larger and more exhaustive list. Requirements never stop changing, so aProduct Backlog is a living artifact. Changes in business requirements, market conditions, ortechnology may cause changes in the Product Backlog.
Multiple Scrum Teams often work together on the same product. One Product Backlog is usedto describe the upcoming work on the product. A Product Backlog attribute that groups itemsmay then be employed.
Product Backlog refinement is the act of adding detail, estimates, and order to items in theProduct Backlog. This is an ongoing process in which the Product Owner and the DevelopmentTeam collaborate on the details of Product Backlog items. During Product Backlog refinement,items are reviewed and revised. The Scrum Team decides how and when refinement is done.Refinement usually consumes no more than 10% of the capacity of the Development Team.However, Product Backlog items can be updated at any time by the Product Owner or at theProduct Owner’s discretion.
Higher ordered Product Backlog items are usually clearer and more detailed than lower orderedones. More precise estimates are made based on the greater clarity and increased detail; thelower the order, the less detail. Product Backlog items that will occupy the Development Teamfor the upcoming Sprint are refined so that any one item can reasonably be “Done” within theSprint time-box. Product Backlog items that can be “Done” by the Development Team withinone Sprint are deemed “Ready” for selection in a Sprint Planning. Product Backlog items usuallyacquire this degree of transparency through the above described refining activities.
The Development Team is responsible for all estimates. The Product Owner may influence theDevelopment Team by helping it understand and select trade-offs, but the people who willperform the work make the final estimate.
Monitoring Progress Toward Goals
At any point in time, the total work remaining to reach a goal can be summed. The ProductOwner tracks this total work remaining at least every Sprint Review. The Product Ownercompares this amount with work remaining at previous Sprint Reviews to assess progresstoward completing projected work by the desired time for the goal. This information is madetransparent to all stakeholders.
Various projective practices upon trending have been used to forecast progress, like burn-downs, burn-ups, or cumulative flows. These have proven useful. However, these do not replacethe importance of empiricism. In complex environments, what will happen is unknown. Onlywhat has already happened may be used for forward-looking decision-making.
Sprint Backlog
The Sprint Backlog is the set of Product Backlog items selected for the Sprint, plus a plan fordelivering the product Increment and realizing the Sprint Goal. The Sprint Backlog is a forecastby the Development Team about what functionality will be in the next Increment and the workneeded to deliver that functionality into a “Done” Increment.
The Sprint Backlog makes visible all the work that the Development Team identifies as necessaryto meet the Sprint Goal. To ensure continuous improvement, it includes at least one highpriority process improvement identified in the previous Retrospective meeting.
The Sprint Backlog is a plan with enough detail that changes in progress can be understood inthe Daily Scrum. The Development Team modifies the Sprint Backlog throughout the Sprint, andthe Sprint Backlog emerges during the Sprint. This emergence occurs as the Development Teamworks through the plan and learns more about the work needed to achieve the Sprint Goal.
As new work is required, the Development Team adds it to the Sprint Backlog. As work isperformed or completed, the estimated remaining work is updated. When elements of the planare deemed unnecessary, they are removed. Only the Development Team can change its SprintBacklog during a Sprint. The Sprint Backlog is a highly visible, real-time picture of the work thatthe Development Team plans to accomplish during the Sprint, and it belongs solely to theDevelopment Team.
Monitoring Sprint Progress
At any point in time in a Sprint, the total work remaining in the Sprint Backlog can be summed.The Development Team tracks this total work remaining at least for every Daily Scrum to projectthe likelihood of achieving the Sprint Goal. By tracking the remaining work throughout theSprint, the Development Team can manage its progress.
Increment
The Increment is the sum of all the Product Backlog items completed during a Sprint and thevalue of the increments of all previous Sprints. At the end of a Sprint, the new Increment mustbe “Done,” which means it must be in useable condition and meet the Scrum Team’s definitionof “Done.” An increment is a body of inspectable, done work that supports empiricism at theend of the Sprint. The increment is a step toward a vision or goal. The increment must be inuseable condition regardless of whether the Product Owner decides to release it.
Scrum relies on transparency. Decisions to optimize value and control risk are made based onthe perceived state of the artifacts. To the extent that transparency is complete, these decisionshave a sound basis. To the extent that the artifacts are incompletely transparent, thesedecisions can be flawed, value may diminish and risk may increase.
The Scrum Master must work with the Product Owner, Development Team, and other involvedparties to understand if the artifacts are completely transparent. There are practices for copingwith incomplete transparency; the Scrum Master must help everyone apply the mostappropriate practices in the absence of complete transparency. A Scrum Master can detectincomplete transparency by inspecting the artifacts, sensing patterns, listening closely to what isbeing said, and detecting differences between expected and real results.
The Scrum Master’s job is to work with the Scrum Team and the organization to increase thetransparency of the artifacts. This work usually involves learning, convincing, and change.Transparency doesn’t occur overnight, but is a path.
Definition of “Done”
When a Product Backlog item or an Increment is described as “Done”, everyone mustunderstand what “Done” means. Although this may vary significantly per Scrum Team, membersmust have a shared understanding of what it means for work to be complete, to ensuretransparency. This is the definition of “Done” for the Scrum Team and is used to assess whenwork is complete on the product Increment.
The same definition guides the Development Team in knowing how many Product Backlog itemsit can select during a Sprint Planning. The purpose of each Sprint is to deliver Increments ofpotentially releasable functionality that adhere to the Scrum Team’s current definition of“Done.”
Development Teams deliver an Increment of product functionality every Sprint. This Incrementis useable, so a Product Owner may choose to immediately release it. If the definition of "Done"for an increment is part of the conventions, standards or guidelines of the developmentorganization, all Scrum Teams must follow it as a minimum.
If "Done" for an increment is not a convention of the development organization, theDevelopment Team of the Scrum Team must define a definition of “Done” appropriate for theproduct. If there are multiple Scrum Teams working on the system or product release, theDevelopment Teams on all the Scrum Teams must mutually define the definition of “Done.”
Each Increment is additive to all prior Increments and thoroughly tested, ensuring that allIncrements work together.
As Scrum Teams mature, it is expected that their definitions of “Done” will expand to includemore stringent criteria for higher quality. New definitions, as used, may uncover work to bedone in previously “Done” increments. Any one product or system should have a definition of“Done” that is a standard for any work done on it.
Scrum is free and offered in this Guide. Scrum’s roles, events, artifacts, and rules are immutableand although implementing only parts of Scrum is possible, the result is not Scrum. Scrum existsonly in its entirety and functions well as a container for other techniques, methodologies, andpractices.
People
Of the thousands of people who have contributed to Scrum, we should single out those whowere instrumental at the start: Jeff Sutherland worked with Jeff McKenna and JohnScumniotales, and Ken Schwaber worked with Mike Smith and Chris Martin, and all of themworked together. Many others contributed in the ensuing years and without their help Scrumwould not be refined as it is today.
History
Ken Schwaber and Jeff Sutherland worked on Scrum until 1995, when they co-presented Scrumat the OOPSLA Conference in 1995. This presentation essentially documented the learning thatKen and Jeff gained over the previous few years, and made public the first formal definition ofScrum.
The history of Scrum is described elsewhere. To honor the first places where it was tried andrefined, we recognize Individual, Inc., Newspage, Fidelity Investments, and IDX (now GEMedical).
The Scrum Guide documents Scrum as developed, evolved, and sustained for 20-plus years byJeff Sutherland and Ken Schwaber. Other sources provide you with patterns, processes, andinsights that complement the Scrum framework. These may increase productivity, value,creativity, and satisfaction with the results.
