Scrum (development)
Encyclopedia
Scrum is an iterative, incremental
framework for project management often seen in agile software development
, a type of software engineering
.
Although the Scrum approach was originally suggested for managing product development
projects, its use has focused on the management of software development projects, and it can be used to run software maintenance teams or as a general project/program management approach.
and Ikujiro Nonaka
described a new approach to commercial product development
that would increase speed and flexibility, based on case studies from manufacturing firms in the automotive, computer, photocopier, and printer industries. They called this the holistic or rugby
approach, as the whole process is performed by one cross-functional team across multiple overlapping phases, where the team "tries to go the distance as a unit, passing the ball back and forth".
In 1991, DeGrace and Stahl first referred to this as the scrum approach In rugby, a scrum
refers to the manner of restarting the game after a minor infraction. In the early 1990s, Ken Schwaber
used such an approach at his company, Advanced Development Methods, and Jeff Sutherland
, with John Scumniotales and Jeff McKenna, developed a similar approach at Easel Corporation, and were the first to refer to it using the single word Scrum.
In 1995, Sutherland
and Schwaber
jointly presented a paper describing the Scrum methodology at the Business Object Design and Implementation Workshop held as part of OOPSLA ’95
in Austin, Texas, its first public presentation. 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 describe the method in the book Agile Software Development with Scrum.
Although the word is not an acronym, some companies implementing the process have been known to spell it with capital letters as SCRUM. This may be due to one of Ken Schwaber
’s early papers, which capitalized SCRUM in the title.
Each sprint is preceded by a planning meeting, where the tasks for the sprint are identified and an estimated commitment for the sprint goal is made, and followed by a review or retrospective meeting, where the progress is reviewed and lessons for the next sprint are identified.
During each sprint, the team creates a potentially deliverable product increment (for example, working and tested software). The set of features that go into a 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 or she wants completed. The team then determines how much of this they can commit to complete during the next sprint, and records this in the sprint backlog. During a sprint, no one is allowed to change the sprint backlog, which means that the requirement
s are frozen for that sprint. Development is timeboxed such that the sprint must end on time; if requirements are not completed for any reason they are left out and returned to the product backlog. After a sprint is completed, the team demonstrates how to use the software.
Scrum enables the creation of self-organizing teams by encouraging co-location of all team members, and verbal communication between all team members and disciplines 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.
Like other agile development methodologies, Scrum can be implemented through a wide range of tools. Many companies use universal software tools, such as spreadsheets to build and maintain artifacts such as the sprint backlog. There are also open-source and proprietary software packages dedicated to management of products under the Scrum process. Other organizations implement Scrum without the use of any software tools, and maintain their artifacts in hard-copy forms such as paper, whiteboards, and sticky notes.
).
Product Owner
Team
ScrumMaster
Stakeholders (customers, vendors)
Managers (including Project Managers)
, but also challenged the conventional ideas about such management. Scrum focuses on project management institutions where it is difficult to plan ahead with mechanisms for empirical process control, such as where feedback loops constitute the core element of product development compared to traditional command-and-control oriented management. It represents a radically new approach for planning and managing software projects, bringing decision-making authority to the level of operation properties and certainties. Scrum reduces defects and makes the development process
more efficient, as well as reducing long-term maintenance costs.
At the end of a sprint cycle, two meetings are held: the “Sprint Review Meeting” and the “Sprint Retrospective”
(Return on Investment) is higher.
The Product Backlog, and business value of each listed item is the property of the product owner. The associated development effort is however set by the Team.
The sprint backlog is the property of the team, and all included estimates are provided by the Team. Often an accompanying task board is used to see and change the state of the tasks of the current sprint, like “to do”, “in progress” and “done”.
is a publicly displayed chart showing remaining work in the sprint backlog. Updated every day, it gives a simple view of the sprint progress. It also provides quick visualizations for reference. There are also other types of burndown, for example the release burndown chart that shows the amount of work left to complete the target commitment for a Product Release (normally spanning through multiple iterations) and the alternative release burndown chart, which basically does the same, but clearly shows scope changes to Release Content, by resetting the baseline.
It should not be confused with an earned value chart
.
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 maximizing its benefits.
Team: A cross-functional group of people responsible for managing itself to develop the product.
Product backlog: A prioritized list of high level requirements.
Sprint backlog: A prioritized list of tasks to be completed during the sprint.
Sprint: A time period (typically 2–4 weeks) in which development occurs on a set of backlog items that the Team has committed to. Also commonly referred to as a Time-box.
Sashimi: A report that something is "done". The definition of "done" may vary from one Scrum Team to another, but must be consistent within one team.
Abnormal Termination: The Product Owner can cancel a Sprint if necessary. The Product Owner may do so with input from the team, scrum master or management. For instance, management may wish to cancel a sprint if external circumstances negate the value of the sprint goal. If a sprint is abnormally terminated, the next step is to conduct a new Sprint planning meeting, where the reason for the termination is reviewed.
Planning Poker: In the Sprint Planning Meeting, the team sits down to estimate its effort for the stories in the backlog. The Product Owner needs these estimates, so that he or she is empowered to effectively prioritize items in the backlog and, as a result, forecast releases based on the team’s velocity.
Point Scale: Relates to an abstract point system, used to discuss the difficulty of the story, without assigning actual hours. The most common scale used is a rounded Fibonacci
sequence (1,2,3,5,8,13,20,40,100), although some teams use linear scale (1,2,3,4...), Powers-of-2 (1,2,4,8...), and Clothes size (XS, S, M, L, XL).
Tasks: Added to the story at the beginning of a sprint and broken down into hours. Each task should not exceed 12 hours but it's common for teams to insist that a task take no more than a day to finish.
Definition of Done (DoD): The exit-criteria
to determine whether a product backlog item is complete. In many cases the DoD requires that all regression tests
should be successful.
. Scrum-ban is especially suited for maintenance projects or (system) projects with frequent and unexpected user stories or programming errors. In such cases the time-limited sprints of the Scrum model are of no appreciable use, but Scrum’s daily meetings and other practices can be applied, depending on the team and the situation at hand. Visualization of the work stages and limitations for simultaneous unfinished user stories and defects are familiar from the Kanban model. Using these methods, the team’s workflow
is directed in a way that allows for minimum completion time for each user story or programming error, and on the other hand ensures each team member is constantly employed.
To illustrate each stage of work, teams working in the same space often use post-it notes or a large whiteboard. In the case of decentralized teams, stage-illustration software, such as Assembla
, ScrumWorks, or JIRA
in combination with GreenHopper can be used to visualize each team’s user stories, defects and tasks divided into separate phases.
In their simplest, the tasks or usage stories are categorized into the work stages
If desired, though, the teams can add more stages of work (such as “defined”, “designed”, “tested” or “delivered”). These additional phases can be of assistance if a certain part of the work becomes a bottleneck and the limiting values of the unfinished work cannot be raised. A more specific task division also makes it possible for employees to specialize in a certain phase of work.
There are no set limiting values for unfinished work. Instead, each team has to define them individually by trial and error; a value too small results in workers standing idle for lack of work, whereas values too high tend to accumulate large amounts of unfinished work, which in turn hinders completion times. A rule of thumb worth bearing in mind is that no team member should have more than two simultaneous selected tasks, and that on the other hand not all team members should have two tasks simultaneously.
The major differences between Scrum and Kanban are derived from the fact that, in Scrum work is divided into sprints that last a certain amount of time, whereas in Kanban the workflow is continuous. This is visible in work stage tables, which in Scrum are emptied after each sprint. In Kanban all tasks are marked on the same table. Scrum focuses on teams with multifaceted know-how, whereas Kanban makes specialized, functional teams possible.
Since Scrum-ban is such a new development model, there is not much reference material. Kanban, on the other hand, has been applied in software development at least by Microsoft and Corbis.
(Oxford University Press
, 1995). Today there are records of Scrum used to produce financial products, Internet products, and medical products by ADM.
Other Agile methods
Iterative and incremental development
Iterative and Incremental development is at the liver of a cyclic software development process developed in response to the weaknesses of the waterfall model...
framework for project management often seen in agile software development
Agile software development
Agile software development is a group of software development methodologies based on iterative and incremental development, where requirements and solutions evolve through collaboration between self-organizing, cross-functional teams...
, a type of software engineering
Software engineering
Software Engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, and the study of these approaches; that is, the application of engineering to software...
.
Although the Scrum approach was originally suggested for managing product development
New product development
In business and engineering, new product development is the term used to describe the complete process of bringing a new product to market. A product is a set of benefits offered for exchange and can be tangible or intangible...
projects, its use has focused on the management of software development projects, and it can be used to run software maintenance teams or as a general project/program management approach.
History
In 1986, Hirotaka TakeuchiHirotaka Takeuchi
is dean of the Graduate School of International Corporate Strategy at Hitotsubashi University in Tokyo and was a visiting professor at Harvard Business School in 1989 and 1990....
and Ikujiro Nonaka
Ikujiro Nonaka
is an influential writer and Professor Emeritus at Hitotsubashi University Graduate School of International Corporate Strategy; the First Distinguished Drucker Scholar in Residence at the Drucker School and Institute, Claremont Graduate University; the Xerox Distinguished Faculty Scholar,...
described a new approach to commercial product development
New product development
In business and engineering, new product development is the term used to describe the complete process of bringing a new product to market. A product is a set of benefits offered for exchange and can be tangible or intangible...
that would increase speed and flexibility, based on case studies from manufacturing firms in the automotive, computer, photocopier, and printer industries. They called this the holistic or rugby
Rugby football
Rugby football is a style of football named after Rugby School in the United Kingdom. It is seen most prominently in two current sports, rugby league and rugby union.-History:...
approach, as the whole process is performed by one cross-functional team across multiple overlapping phases, where the team "tries to go the distance as a unit, passing the ball back and forth".
In 1991, DeGrace and Stahl first referred to this as the scrum approach In rugby, a scrum
Scrum (rugby)
Scrum , in the sports of rugby union and rugby league, is a way of restarting the game, either after an accidental infringement or when the ball has gone out of play...
refers to the manner of restarting the game after a minor infraction. In the early 1990s, Ken Schwaber
Ken Schwaber
Ken Schwaber is a software developer, product manager and industry consultant. Ken worked with Jeff Sutherland to formulate the initial versions of the Scrum development process and to present Scrum as a formal process at OOPSLA'95. They have extended and enhanced Scrum at many software companies...
used such an approach at his company, Advanced Development Methods, and Jeff Sutherland
Jeff Sutherland
Dr. Jeff Sutherland is one of the inventors of the Scrum software development process. Together with Ken Schwaber, he created Scrum as a formal process at OOPSLA'95...
, with John Scumniotales and Jeff McKenna, developed a similar approach at Easel Corporation, and were the first to refer to it using the single word Scrum.
In 1995, Sutherland
Jeff Sutherland
Dr. Jeff Sutherland is one of the inventors of the Scrum software development process. Together with Ken Schwaber, he created Scrum as a formal process at OOPSLA'95...
and Schwaber
Ken Schwaber
Ken Schwaber is a software developer, product manager and industry consultant. Ken worked with Jeff Sutherland to formulate the initial versions of the Scrum development process and to present Scrum as a formal process at OOPSLA'95. They have extended and enhanced Scrum at many software companies...
jointly presented a paper describing the Scrum methodology at the Business Object Design and Implementation Workshop held as part of OOPSLA ’95
OOPSLA
OOPSLA is an annual ACM research conference. OOPSLA mainly takes place in the United States, while the sister conference of OOPSLA, ECOOP, is typically held in Europe...
in Austin, Texas, its first public presentation. 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 describe the method in the book Agile Software Development with Scrum.
Although the word is not an acronym, some companies implementing the process have been known to spell it with capital letters as SCRUM. This may be due to one of Ken Schwaber
Ken Schwaber
Ken Schwaber is a software developer, product manager and industry consultant. Ken worked with Jeff Sutherland to formulate the initial versions of the Scrum development process and to present Scrum as a formal process at OOPSLA'95. They have extended and enhanced Scrum at many software companies...
’s early papers, which capitalized SCRUM in the title.
Characteristics
Scrum is a process skeleton that contains sets of practices and predefined roles. The main roles in Scrum are:- the “ScrumMaster”, who maintains the processes (typically in lieu of a project managerProject managerA project manager is a professional in the field of project management. Project managers can have the responsibility of the planning, execution, and closing of any project, typically relating to construction industry, architecture, computer networking, telecommunications or software...
) - the “Product Owner”, who represents the stakeholders and the business
- the “Team”, a cross-functional group who do the actual analysis, design, implementation, testing, etc.
Sprint
A sprint is the basic unit of development in Scrum. Sprints tend to last between one week and one month, and are a "timeboxed" (i.e. restricted to a specific duration) effort of a constant length.Each sprint is preceded by a planning meeting, where the tasks for the sprint are identified and an estimated commitment for the sprint goal is made, and followed by a review or retrospective meeting, where the progress is reviewed and lessons for the next sprint are identified.
During each sprint, the team creates a potentially deliverable product increment (for example, working and tested software). The set of features that go into a 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 or she wants completed. The team then determines how much of this they can commit to complete during the next sprint, and records this in the sprint backlog. During a sprint, no one is allowed to change the sprint backlog, which means that the requirement
Requirement
In engineering, a requirement is a singular documented physical and functional need that a particular product or service must be or perform. It is most commonly used in a formal sense in systems engineering, software engineering, or enterprise engineering...
s are frozen for that sprint. Development is timeboxed such that the sprint must end on time; if requirements are not completed for any reason they are left out and returned to the product backlog. After a sprint is completed, the team demonstrates how to use the software.
Scrum enables the creation of self-organizing teams by encouraging co-location of all team members, and verbal communication between all team members and disciplines 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.
Like other agile development methodologies, Scrum can be implemented through a wide range of tools. Many companies use universal software tools, such as spreadsheets to build and maintain artifacts such as the sprint backlog. There are also open-source and proprietary software packages dedicated to management of products under the Scrum process. Other organizations implement Scrum without the use of any software tools, and maintain their artifacts in hard-copy forms such as paper, whiteboards, and sticky notes.
Roles
Scrum teams consist of three core roles and a range of ancillary roles—core roles are often referred to as pigs and ancillary roles as chickens (after the story The Chicken and the PigThe Chicken and the Pig
-Content:The basic fable runs:-Agile Project Management:The fable is referenced to define two types of project members by the scrum agile management system: pigs, who are totally committed to the project and accountable for its outcome, and chickens, who consult on the project and are informed of...
).
Core Scrum roles
The core roles in Scrum teams are those committed to the project in the Scrum process—they are the ones producing the product (objective of the project).Product Owner
- The Product Owner represents the voice of the customerVoice of the customerVoice of the customer is a term used in business and Information Technology to describe the in-depth process of capturing a customer's expectations, preferences and aversions...
and is accountable for ensuring that the Team delivers value to the business. The Product Owner writes customer-centric items (typically user storiesUser storyIn computer programming a user story is one or more sentences in the everyday or business language of the end user that captures what the user wants to achieve. User stories are used with Agile software development methodologies for the basis of what features that can be implemented...
), prioritizes them, and adds them to the product backlog. Scrum teams should have one Product Owner, and while they may also be a member of the Development Team, it is recommended that this role not be combined with that of ScrumMaster.
Team
- The Team is responsible for delivering the product. A Team is typically made up of 5–9 people with cross-functional skills who do the actual work (analyse, design, develop, test, technical communication, document, etc.). It is recommended that the Team be self-organizing and self-led, but often work with some form of project or team management.
ScrumMaster
- Scrum is facilitated by a ScrumMaster, also written as Scrum Master, who is accountable for removing impediments to the ability of the team to deliver the sprint goal/deliverables. The ScrumMaster is not the team leader 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. A key part of the ScrumMaster’s role is to protect the team and keep them focused on the tasks at hand. The role has also been referred to as servant-leader to reinforce these dual perspectives.
Ancillary Scrum roles
The ancillary roles in Scrum teams are those with no formal role and infrequent involvement in the Scrum process—but nonetheless, must be taken into account.Stakeholders (customers, vendors)
- These are the people who enable the project and for whom the project will produce the agreed-upon benefit[s], which justify its production. They are only directly involved in the process during the sprint reviews.
Managers (including Project Managers)
- People who will set up the environment for product development.
Agile Project Management with Scrum
Scrum has not only reinforced the interest in software project managementSoftware project management
Software project management is the art and science of planning and leading software projects. It is a sub-discipline of project management in which software projects are planned, monitored and controlled.-History:...
, but also challenged the conventional ideas about such management. Scrum focuses on project management institutions where it is difficult to plan ahead with mechanisms for empirical process control, such as where feedback loops constitute the core element of product development compared to traditional command-and-control oriented management. It represents a radically new approach for planning and managing software projects, bringing decision-making authority to the level of operation properties and certainties. Scrum reduces defects and makes the development process
Software development process
A software development process, also known as a software development life cycle , is a structure imposed on the development of a software product. Similar terms include software life cycle and software process. It is often considered a subset of systems development life cycle...
more efficient, as well as reducing long-term maintenance costs.
Daily Scrum
- Each day during the sprint, a project status meeting occurs. This is called a daily scrum, or the daily standup. This meeting has specific guidelines:
- The meeting starts precisely on time.
- All are welcome, but normally only the core roles speak
- The meeting is timeboxed to 15 minutes
- The meeting should happen at the same location and same time every day
- During the meeting, each team member answers three questions:
- What have you done since yesterday?
- What are you planning to do today?
- Any impediments/stumbling blocks?
- It is the role of the ScrumMaster to facilitate resolution of these impediments, although the resolution should occur outside the Daily Scrum itself to keep it under 15 minutes.
Scrum of scrums
- Each day normally after the daily scrum.
- These meetings allow clusters of teams to discuss their work, focusing especially on areas of overlap and integration.
- A designated person from each team attends.
- The agenda will be the same as the Daily Scrum, plus the following four questions:
- What has your team done since we last met?
- What will your team do before we meet again?
- Is anything slowing your team down or getting in their way?
- Are you about to put something in another team’s way?
Sprint Planning Meeting
- At the beginning of the sprint cycle (every 7–30 days), a “Sprint Planning Meeting” is held.
- Select what work is to be done
- Prepare the Sprint Backlog that details the time it will take to do that work, with the entire team
- Identify and communicate how much of the work is likely to be done during the current sprint
- Eight hour time limit
- (1st four hours) Product Owner + Team: dialog for prioritizing the Product Backlog
- (2nd four hours) Team only: hashing out a plan for the Sprint, resulting in the Sprint Backlog
At the end of a sprint cycle, two meetings are held: the “Sprint Review Meeting” and the “Sprint Retrospective”
Sprint Review Meeting
- Review the work that was completed and not completed
- Present the completed work to the stakeholders (a.k.a. “the demo”)
- Incomplete work cannot be demonstrated
- Four hour time limit
Sprint Retrospective
- All team members reflect on the past sprint
- Make continuous process improvements
- Two main questions are asked in the sprint retrospective: What went well during the sprint? What could be improved in the next sprint?
- Three hour time limit
Product backlog
The product backlog is a high-level list that is maintained throughout the entire project. It aggregates backlog items: broad descriptions of all potential features, prioritized as an absolute ordering by business value. It is therefore the “What” that will be built, sorted by importance. It is open and editable by anyone and contains rough estimates of both business value and development effort. Those estimates help the Product Owner to gauge the timeline and, to a limited extent prioritize. For example, if the “add spellcheck” and “add table support” features have the same business value, the one with the smallest development effort will probably have higher priority, because the ROIReturn on investment
Return on investment is one way of considering profits in relation to capital invested. Return on assets , return on net assets , return on capital and return on invested capital are similar measures with variations on how “investment” is defined.Marketing not only influences net profits but also...
(Return on Investment) is higher.
The Product Backlog, and business value of each listed item is the property of the product owner. The associated development effort is however set by the Team.
Sprint backlog
The sprint backlog is the list of work the team must address during the next sprint. Features are broken down into tasks, which, as a best practice, should normally be between four and sixteen hours of work. With this level of detail the whole team understands exactly what to do, and potentially, anyone can pick a task from the list. Tasks on the sprint backlog are never assigned; rather, tasks are signed up for by the team members as needed, according to the set priority and the team member skills. This promotes self-organization of the team, and developer buy-in.The sprint backlog is the property of the team, and all included estimates are provided by the Team. Often an accompanying task board is used to see and change the state of the tasks of the current sprint, like “to do”, “in progress” and “done”.
Burn down
The sprint burn down chartBurn down chart
A burn down chart is a graphical representation of work left to do versus time. The outstanding work is often on the vertical axis, with time along the horizontal. That is, it is a run chart of outstanding work. It is useful for predicting when all of the work will be completed. It is often used...
is a publicly displayed chart showing remaining work in the sprint backlog. Updated every day, it gives a simple view of the sprint progress. It also provides quick visualizations for reference. There are also other types of burndown, for example the release burndown chart that shows the amount of work left to complete the target commitment for a Product Release (normally spanning through multiple iterations) and the alternative release burndown chart, which basically does the same, but clearly shows scope changes to Release Content, by resetting the baseline.
It should not be confused with an earned value chart
Earned value management
Earned value management is a project management technique for measuring project performance and progress in an objective manner. EVM has the ability to combine measurements of scope, schedule, and cost in a single integrated system. Earned Value Management is notable for its ability to provide...
.
Roles
Scrum Team: Product Owner, ScrumMaster and TeamProduct 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 maximizing its benefits.
Team: A cross-functional group of people responsible for managing itself to develop the product.
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 prioritized list of tasks to be completed during the sprint.
Others
Impediment: Anything that prevents a team member from performing work as efficiently as possible.Sprint: A time period (typically 2–4 weeks) in which development occurs on a set of backlog items that the Team has committed to. Also commonly referred to as a Time-box.
Sashimi: A report that something is "done". The definition of "done" may vary from one Scrum Team to another, but must be consistent within one team.
Abnormal Termination: The Product Owner can cancel a Sprint if necessary. The Product Owner may do so with input from the team, scrum master or management. For instance, management may wish to cancel a sprint if external circumstances negate the value of the sprint goal. If a sprint is abnormally terminated, the next step is to conduct a new Sprint planning meeting, where the reason for the termination is reviewed.
Planning Poker: In the Sprint Planning Meeting, the team sits down to estimate its effort for the stories in the backlog. The Product Owner needs these estimates, so that he or she is empowered to effectively prioritize items in the backlog and, as a result, forecast releases based on the team’s velocity.
Point Scale: Relates to an abstract point system, used to discuss the difficulty of the story, without assigning actual hours. The most common scale used is a rounded Fibonacci
Fibonacci number
In mathematics, the Fibonacci numbers are the numbers in the following integer sequence:0,\;1,\;1,\;2,\;3,\;5,\;8,\;13,\;21,\;34,\;55,\;89,\;144,\; \ldots\; ....
sequence (1,2,3,5,8,13,20,40,100), although some teams use linear scale (1,2,3,4...), Powers-of-2 (1,2,4,8...), and Clothes size (XS, S, M, L, XL).
Tasks: Added to the story at the beginning of a sprint and broken down into hours. Each task should not exceed 12 hours but it's common for teams to insist that a task take no more than a day to finish.
Definition of Done (DoD): The exit-criteria
Exit-criteria
Exit criteria are the criteria or requirements which must be met to complete a specific process.For example for Fagan Inspection the low-level document must comply with specific exit-criteria before the development process can be taken to the next phase.In telecommunications, when testing new...
to determine whether a product backlog item is complete. In many cases the DoD requires that all regression tests
Regression testing
Regression testing is any type of software testing that seeks to uncover new errors, or regressions, in existing functionality after changes have been made to a system, such as functional enhancements, patches or configuration changes....
should be successful.
Scrum-ban
Scrum-ban is a software production model based on Scrum and KanbanKanban (development)
Kanban is a method for developing products with an emphasis on just-in-time delivery while not overloading the developers. It emphasizes that developers pull work from a queue, and the process, from definition of a task to its delivery to the customer, is displayed for participants to see.Kanban...
. Scrum-ban is especially suited for maintenance projects or (system) projects with frequent and unexpected user stories or programming errors. In such cases the time-limited sprints of the Scrum model are of no appreciable use, but Scrum’s daily meetings and other practices can be applied, depending on the team and the situation at hand. Visualization of the work stages and limitations for simultaneous unfinished user stories and defects are familiar from the Kanban model. Using these methods, the team’s workflow
Workflow
A workflow consists of a sequence of connected steps. It is a depiction of a sequence of operations, declared as work of a person, a group of persons, an organization of staff, or one or more simple or complex mechanisms. Workflow may be seen as any abstraction of real work...
is directed in a way that allows for minimum completion time for each user story or programming error, and on the other hand ensures each team member is constantly employed.
To illustrate each stage of work, teams working in the same space often use post-it notes or a large whiteboard. In the case of decentralized teams, stage-illustration software, such as Assembla
Assembla
Assembla is a collaborative project management service for open-source and commercial software. The service rents development applications to other companies online, reducing the cost of software development.-History:...
, ScrumWorks, or JIRA
JIRA
Jira may refer to:* JIRA, software-engineering package* Journal of Iranian Research and Analysis* Jira, also known as Zilla, fictional character* Jira * Jira...
in combination with GreenHopper can be used to visualize each team’s user stories, defects and tasks divided into separate phases.
In their simplest, the tasks or usage stories are categorized into the work stages
- Unstarted
- Ongoing
- Completed
If desired, though, the teams can add more stages of work (such as “defined”, “designed”, “tested” or “delivered”). These additional phases can be of assistance if a certain part of the work becomes a bottleneck and the limiting values of the unfinished work cannot be raised. A more specific task division also makes it possible for employees to specialize in a certain phase of work.
There are no set limiting values for unfinished work. Instead, each team has to define them individually by trial and error; a value too small results in workers standing idle for lack of work, whereas values too high tend to accumulate large amounts of unfinished work, which in turn hinders completion times. A rule of thumb worth bearing in mind is that no team member should have more than two simultaneous selected tasks, and that on the other hand not all team members should have two tasks simultaneously.
The major differences between Scrum and Kanban are derived from the fact that, in Scrum work is divided into sprints that last a certain amount of time, whereas in Kanban the workflow is continuous. This is visible in work stage tables, which in Scrum are emptied after each sprint. In Kanban all tasks are marked on the same table. Scrum focuses on teams with multifaceted know-how, whereas Kanban makes specialized, functional teams possible.
Since Scrum-ban is such a new development model, there is not much reference material. Kanban, on the other hand, has been applied in software development at least by Microsoft and Corbis.
Product development
Scrum as applied to product development was first referred to in "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 TakeuchiHirotaka Takeuchi
is dean of the Graduate School of International Corporate Strategy at Hitotsubashi University in Tokyo and was a visiting professor at Harvard Business School in 1989 and 1990....
(Oxford University Press
Oxford University Press
Oxford University Press is the largest university press in the world. It is a department of the University of Oxford and is governed by a group of 15 academics appointed by the Vice-Chancellor known as the Delegates of the Press. They are headed by the Secretary to the Delegates, who serves as...
, 1995). Today there are records of Scrum used to produce financial products, Internet products, and medical products by ADM.
Evaluation
There isn't a lot of proof that adopting SCRUM will lead to good results in any specific environment. Parameters such as usability of sprints and their duration are just given. It must still prove itself. Other issues that should be mentioned are large uncertainties in fitness for various types of projects, environments, cultures, team compositions and many other parameters. It also suffers from the take-up by commercial parties wanting to use this as a cookbook for commercial success. Where true insight into Agile methodologies and concepts is required, SCRUM will not help per se.See also
- KaizenKaizen, Japanese for "improvement", or "change for the better" refers to philosophy or practices that focus upon continuous improvement of processes in manufacturing, engineering, game development, and business management. It has been applied in healthcare, psychotherapy, life-coaching, government,...
- List of software development philosophies
- Code monkeyCode monkeyA Code monkey is a computer programmer or other person who writes computer code for a living. This term may be slightly derogatory, meaning that this developer can write some code but is unable to perform the more complex tasks of software architecture, analysis, and design...
Other Agile methods
- Dynamic System Development Method
- Extreme programmingExtreme ProgrammingExtreme programming is a software development methodology which is intended to improve software quality and responsiveness to changing customer requirements...
(XP) - Feature Driven DevelopmentFeature Driven DevelopmentFeature-driven development is an iterative and incremental software development process. It is one of a number of Agile methods for developing software and forms part of the Agile Alliance. FDD blends a number of industry-recognized best practices into a cohesive whole. These practices are all...
- Lean software developmentLean software developmentLean software development is a translation of Lean manufacturing and Lean IT principles and practices to the software development domain. Adapted from the Toyota Production System, a pro-lean subculture is emerging from within the Agile community....
External links
- Scrum Alliance, Official Scrum Organization, non Profit
- Scrum.org
- Agile Alliance’s Scrum library
- A Scrum Process Description by the Eclipse Process Framework (EPF) Project
- BPMN process diagram of Scrum
- A six-page illustrated Scrum reference
- Burn Down Chart Tutorial: Simple Agile Project Tracking (Scrum)
Videos and slides
- Jeff Sutherland in Scrum Tuning: Lessons learned from Scrum implementation at Google Retrieved 2007-12-15
- Ken Schwaber in Scrum et al. Retrieved 2008-01-19
- Jeff Sutherland in Hyperproductive Distributed Scrum Teams