SCRUM: An extension pattern language for
hyperproductive software development

Mike Beedle beedlem@fti-consulting.com
Martine Devos mdevos@argo.be
Yonat Sharon yonat@usa.net
Ken Schwaber virman@aol.com
Jeff Sutherland jeff.sutherland@idx.com

Abstract
The patterns of the SCRUM development method are presented as anextension pattern language to the existing organizational pattern languages.
In the last few years, the SCRUM development method has rapidly gained
recognition as an effective tool to hyper-productive software development.
However, when SCRUM patterns are combined with other existingorganizational patterns, they lead to highly adaptive, yet well-structured
software development organizations. Also, decomposing SCRUM into
patterns can guide adoption of only those parts of SCRUM that are applicable
to a specific situation.

1. Introduction
NOTE: Throughout this paper we assume the reader is familiar with the other org
patterns [OrgPatt], [Coplien95]. Also all pattern names will be presented in boldeditalics types as in: DeveloperControlsProcess, or ArchitectControlsProduct.
Can a repeatable and defined process really exist for software development? Some think
this is not only possible but necessary, for example those that favor the CMM (Capability
Maturity Model) approach to software development [1]. The CMM defines five stages ofprocess maturity initial, repeatable, defined, managed and optimizing, and ask its users todefine the processes of 18 KPA (key process areas).

However, many of us doing work in the trenches have found over time that the“repeatable or defined” process approach makes many incorrect assumptions, such as:1) Repeatable/defined problem. A repeatable/defined process assumes that
there is a step to capture requirements, but in most cases, it is not possible todefine the requirements of an application, because they are either not welldefined or they keep changing.
2) Repeatable/defined solution. A repeatable/defined process assumes that anarchitecture can be fully specified, but in reality it is evolved, partly due tothe fact of missing or changing requirements (as described above), and partly
because of the creative process involved in creating it.
3) Repeatable/defined developers. The capabilities of a software developer vary
widely, so a process that works for one developer may not work for anotherone.
4) Repeatable/defined organizational environment. The schedule pressure,priorities (say, quality vs. price), client behavior, etc.; are never repeatable ordefined.
The main problem with these assumptions is to assume that any of the above things has
non-chaotic behavior. Even small enough unknowns can have a big influence on the
result.
Because in practical situation the removal of these uncertainties is impossible, many of us
have searched for answers beyond the repeatable/defined approach of softwaredevelopment, to a more “adaptive approach”.
SCRUM assumes up-front the existence of chaos in the items in the list discussed above
as incorrect assumptions, but it provides for techniques to resolve these problems withtechniques rooted in complexity management i.e. self-organization, management of
empirical processes, knowledge creation, etc.
In that sense, SCRUM is not only an "iterative and incremental" development method but
it is also an "adaptive" software development method.

2. How does SCRUM work?
SCRUM’s goal is to deliver as much quality software as possible within a series (3-8), ofshort time-boxes called Sprints that typically last about a month. (Time-boxes areintervals of time.)
Each stage in the development cycle (Requirements, Analysis, Design, Evolution, andDelivery) is now mapped to a Sprint or series of Sprints. The traditional softwaredevelopment stages are retained for convenience primarily for tracking milestones. So,for example, the Requirements stage may use one Sprint, including the delivery of a

prototype. The Analysis and Design stages may take one Sprint each. While the
Evolution stage may take anywhere from 3 to 5 Sprints.
As opposed to a repeatable and defined process approach, in SCRUM there is nopredefined process within a Sprint. Instead, Scrum Meetings drive the completion of theallocated activities.
Each Sprint operates on a number of work items called a Backlog. As a rule, no more
items are externally added into the Backlog within a Sprint. Internal items resulting fromthe original pre-allocated Backlog can be added to it. The goal of a Sprint is to complete
as much quality software as possible, but typically less software is delivered in practice(Worse Is Better pattern). The end result is that there are non-perfect NamedStableBasesdelivered every Sprint.

Figure 1. A rugby team also uses Scrum Meetings (not shown here).
During a Sprint, Scrum Meetings are held each day in order to check on:1) what items were completed since the last Scrum Meeting.
2) what issues or Blocks have been found that need to be resolved. (The
ScrumMaster is a team leader role responsible for resolving the Blocks.)
3) what new assignments make sense for the team to complete until the next
Scrum meeting.
Scrum Meetings allow the development team to "socialize the team members
knowledge", and have a deep cultural transcendence.

In turn, this "knowledge socialization" leads to a self-organized team structure, where theprocess is invented in an adaptable way on a daily basis.
At the end of each Sprint, there is a Demo to:1) show the customer what’s going on, (EngageCustomer)2) give the developer’s a sense of accomplishment (CompensateSuccess)3) integrate and test a reasonable portion of the software being developed(EngageQA)4) ensure real progress – reduction of backlog, not just more papers / hours spent(NamedStableBases)
After gathering and reprioritizing the leftover and new tasks, a new Backlog is formed
and a new Sprint starts. Potentially, many other org patterns may be used in combination
with the SCRUM patterns. While Coplien org patterns (organization and process
patterns), are an obvious choice because of their breadth, other org patterns from othersources may also be very valuable [OrgPatt], [Coplien95].
“The system requires it” or the “The system does not allow it “ have become accepted(and often unavoidable) justifications of human behavior. What we fear is that current
methods do not allow us to build soft enough software, because present methods anddesign paradigms seem to inhibit adaptability. Therefore the majority of software
practitioners tend to become experts at what they can specify in advance, working withthe unstated belief that there exists an optimal solution that can be planned a priori.
Once technology is adopted by an organization, it often becomes a constraining structurethat in part shapes the action space of the user. So we build software too much like webuild hardware, as if it was difficult to change, and as if it has to be difficult to change.
In contrast SCRUM allows us to build softer software, so there is no use trying to write
full requirements up front. The user does not know what is possible and will ask for the
pre-tech-paper solution that he perceives to be possible. But not even the softwaredevelopers know fully what can be built before it is. And therefore the user has no clueof what is possible before he can feel it, or touch it [Blu96].
As such we need another softer approach for building software. So we are better off byrealizing that it is impossible to have full requirements specified up-front or to freeze thecontext and environment. Requirements are written in a context. Our system transforms
that context. New problems arise in the system and the new context.
This issue is not solved through improved methods for identifying the user requirements.
Instead they call for a more complex process of generating fundamentally new operating
alternatives. The empirical way of working in Scrum is one of the possible alternatives.

3. The SCRUM Pattern Language
The following diagram shows the relationships among the SCRUM patterns and other org
patterns.
DeveloperControlsProcess

FirewallScrumMasterScrumTeam
Demo

Hyperlinked Org

SprintEngageQA
Backlog

NamedStableBases

ScrumMeetings

Figure 2. SCRUM Pattern Language Lattice (Coplien = yellow, SCRUM=blue)

4. The Patterns of Scrum

Scrum Meeting
Context(FROM: Backlog)
You if you are a software developer or a coach managing a software development team
where there is a high percentage of discovery, creativity or testing involved. For
example, a first time delivery where the problem has to be specified, or an object modelhas to be created, or new or changing technologies are being used.
Activities such as scientific research, innovation, invention, architecture, engineering anda myriad of other business situations may also exhibit this behavior.
You may also be a "knowledge worker", an engineer, a writer, a research scientist, or an
artist; or a coach or manager that is overseeing the activities of a team in theseenvironments.
(Misfit variables: estimation, planning, tracking, human comfort)
NOTE: Misfit variables are variables in the context that can adjusted to fit the solution tosolve the problem.

Problem
What is the best way to control an empirical and unpredictable process such as softwaredevelopment, scientific research, artistic projects or innovative designs where is hard to
define the artifacts to be produced and the processes to achieve them?

Forces (Analysis of Misfit Variables in the Context)[NOTE: MISFIT examples are referred by some as anti-patterns. I use here some
Dilbert-like names to indicate their awry nature.]
Estimation(+) Accurate estimation for activities involving discovery, creativity or testing isdifficult because it typically involves large variances, and because small
differences in circumstances may cause significant differences in results.
These uncertainties come in at least 4 flavors:a)Requirements are not well understood.

b)Architectural dependencies are not easy to understand and are constantly
changing.

c)There may be unforeseen technical challenges with the technology, etc. Even
if the challenges are known in advance, their solutions and related effort are
not known.

d) There may be hard bugs to resolve in the software, and therefore, it is typicalto see project estimates that are several orders of magnitude off. You can’t“plan bugs”. You can only plan bug handling and prevention schemes, and to
do this, you must first accept the possibility of unexpected bugs.
MISFIT example: YouGotTheWrongNumber In projects capturing new orchanging requirements, a new architecture, new or changing technologies, anddifficult bugs to weed out; it is typical to see project estimates that are several
hundreds of a percent off.
(-) Estimation is important. One must be able to determine what are the futuretasks within some time horizon and prepare resources in advance.
MISFIT example: SetMeUpForFailure Projects where no estimation is done are
difficult to manage.

Planning(+) Planning and reprioritizing tasks takes time. Using the knowledge workers’
time planning meeting decreases productivity. Moreover, if the system is chaotic,
no amount of planning can reduce the uncertainties in results.
MISFIT example: ParalysisByPlanning Projects that waste everybody’s time inplanning everything to an extreme detail but are never able to meet the plans.
(+) A plan that is too detailed becomes huge and hard to follow. It may be easier
to just apply common sense or call the customer. Also, the bigger the plan, themore errors it will contain (alternatively, the cost of verifying its correctness
grows).
(-) No planning at all increases uncertainty among team members, and it would
eventually damage morale.
MISFIT example: LostVision Projects that never schedule anything tend to lose
control over their expectations. Without some scheduling pressure no one will doanything, but worse, it will become difficult to integrate together the different
parts being worked on independently.
Tracking(+) Too much monitoring wastes time and suffocates developers.
(+) Tracking does not increase the certainty of the indicators because of thechaotic nature of the system.
(+) Too much data is meaningless - The Haystack Syndrome.
MISFIT example: MeasuredToDeath Projects that waste everybody’s time intracking everything to an extreme detail but are never able to meet the plans.
(You measured the tire pressure until all the air was out!)(-) Not enough monitoring leads to Blocks and possible idle time between
assignments.
MISFIT example: WhatHappenedHere? Projects that never track anything tend
to lose control over what is being done. And eventually no one really knows what
has been done.

Solution(A thing, albeit temporary)
Meet with the team members for a short time (~15 minutes) in a daily Scrum Meeting,where each participant only answers the following 3 questions:(A process, and what stays the same)1) What they worked in the last 24 hrs. The ScrumMaster logs what tasks have been
completed and what remains undone.
2) What blocks if any they found in performing their tasks within the last 24 hrs. The
ScrumMaster logs all blocks and later finds a way to resolve the blocks.
3) What they will be working in the next 24 hrs. The ScrumMaster helps the teammembers choosing the appropriate tasks to work on with the help of the Architect.
Because the tasks are schedule on a 24 hr basis the tasks are typically small(SmallAssignments).
Scrum Meetings typically take place at the same time and place every day, because theyalso serve to build a strong culture. As such, Scrum Meetings are rituals that enhance thesocialization of status, issues, and plans for the team. The ScrumMaster leads themeetings and logs all the tasks from every member of the team into a global project
Backlog. He also logs every block and resolves each block while the developers work on
new assignments.
Scrum Meetings not only schedule tasks for the developers but can and should schedule
activities for everyone involved in the project such as integration personnel dedicated toconfiguration management, architects, ScrumMasters, Firewall, Coach, QA team.
Scrum Meetings allow knowledge workers to accomplish mid-term goals typicallyallocated in Sprints that last for about a month.
(what changes)
SCRUMs can also be held by self-directed teams, in that case, someone is designated as
the scribe and logs the completed and planned activities of the Backlog and the existing
Blocks. All activities from the Backlog and the blocks are then distributed among theteam members for resolution.
The format of the Backlog and the blocks can also vary, ranging from a list of items in apiece of paper, to software representations of it over the INTERNET/INTRANET[Schwaber97]. The Scrum cycle can be adjusted but typically ranges between 2 hrs, and48 hrs.

Rationale
It is very easy to under- or over- shoot an estimate, which leads to idle developer’s timeor to delays in the completion of an assignments respectively. It is better to sample
frequently the status of small assignments. Processes with a high degree of
unpredictability cannot use traditional project planning techniques only, such as Gantt or
PERT charts because the rate of change of what is being analyzed, accomplished, or
created is too high. Instead, constant reprioritization of tasks offers an adaptive
mechanism that provides sampling of systemic knowledge over short periods of time.

SCRUM meetings help also in the creation of an "anticipating culture” [Weinberg97],
because they encourage productive values:••••

increase the overall sense of urgency,
promote the sharing of knowledge,
encourage dense communications andfacilitate "honesty" among developers since everyone has to give a daily
status.

This same mechanism, encourages team members to socialize, externalize, internalize
and combine technical knowledge on an ongoing basis, thus allowing technical expertiseto become community property for the community of practice [Nonaka95]. Scrum
Meetings are therefore rituals with deep cultural transcendence. Meeting at the sameplace at the same time, and with the same people, enhances feel of belonging, and creates
the habit of sharing knowledge.
Seen from the System Dynamics point of view [Senge94], software development has ascheduling problem, because the nature of programming assignments has a rather
probabilistic nature and estimates are hard to come by because:
1) Inexperienced developers, managers and architects are involved in making theestimates
2) There are typically interlocking architectural dependencies that are hard to manage
3) There are unknown or poorly documented requirements, or4) There are unforeseen technical challenges
Therefore software development becomes a chaotic beer game, where it is hard to
estimate and control the inventory of available developer's time, unless increased
monitoring of small assignments is implemented [Goldratt90], [Senge90]. In that sense
the Scrum Meeting becomes the equivalent of a thermometer that constantly samples theteam’s temperature [Schwaber97-2].
From the Complexity Theory perspective, SCRUM allows flocking by forcing a fasteragent interaction, therefore accelerating the process of self-organization, because it shifts
resources opportunistically, through the daily SCRUM meetings.
This is understandable, because the relaxation of a self-organized multi-agent system is
proportional to the average exchange among agents per unit of time. And in fact, the"interaction rate" is one of the levers one can push to control "emergent" behavior -- it islike adding an enzyme to a chemical reaction.
In SCRUM this means increasing the frequency of the SCRUM meetings, and allowing
more hyperlinks as described below, but up to an optimizing upper frequency bound on
the SCRUM meetings (meetings/time), and up to an optimizing upper bound on thehyper-links or the SCRUM team members. Otherwise the organization spends too muchtime socializing knowledge, instead of performing tasks.

Examples(Mike Beedle) At Nike Securities in Chicago we have been using SCRUM meetings
since February 1997 to run all of our projects including BPR and software development.
Everyone involved in these projects receives a week of training in SCRUM techniques.
(Yonat Sharon) At Elementrix Technologies we had a project that was running way past
late after about 5 months of development. Only a small part of the scope (about 20%) wascompleted and even this part had too many bugs. The project manager started running bidaily short status meetings (none of us was familiar with the term SCRUM back then). In
the following month, the entire scope was competed and the quality has risen sharply.
Two weeks later, a beta version was out. The meetings were later discontinued, and the
project hardly progressed since. I don’t think this can be attributed to the Scrum Meetings
alone, but they did have a big part in this achievement.
One of my software team leaders at RAFAEL, implemented a variation of Scrum
Meetings. He would visit each developer once a day, and ask him the 3 questions, andhe also managed a backlog. This does not have the team building effects, but it does
provide the frequent sampling.

Resulting Context
A structure such as DeveloperControlsProcess is fully implemented throughFormFollowsFunction, or a CaseTeam in a business environment, is jelled into a highly
adaptable and hyperproductive team structure.
As a result, the application of this pattern also leads to:
•
•
•
•
•

highly visible project status.
highly visible individual productivity.
less time wasted because of blocks.
less time wasted because of waiting for someone else.
increased Team Socialization

Sprint
Context(FROM: DeveloperControlsProcess [Coplien95], CompressTheProcess [Beedle97],
SelfSelectingTeam [Coplien95])
You are a software developer or a coach managing a software development team where
there is a high percentage of discovery, creativity or testing involved.
Scrum Meetings and Sprints are applicable for building systems, both new and existing,that allow partitioning of work, with clean interfacing, components or objects.
We want every person on the team to understand the problem fully and to be aware of all
the steps in development. This limits the size of the team and of the system developed.
Trust is a core value in Scrum, and especially important for the success of Sprints, so
SelfSelectingTeams is a plus.
During a sprint, we optimize communications and maximize information sharing in daily
Scrum Meetings.
Each Sprint takes a pre-allocated amount of work from the Backlog. The team commits
to it. As a rule nothing is added externally during a sprint. External additions are added to
the global backlog. Issues resulting from the Sprint can also be added to the Backlog. A
Sprint ends with a Demonstration of new functionality.

Problem
We want to balance the need of developers to work undisturbed and the need for
management and the customer to see real progress.

ForcesFor many people – project managers, customers, it is difficult to give up control andproof of progress as provided in traditional development. It feels risky to do so; there is
no guarantee that the team will deliver.
Often, by the time systems are delivered, it is obsolete or it requires major changes. The
problem is that input from the environment is mostly collected at the start of the project,while the user learns most using the system or intermediate releases.

Some problems are “wicked”, that is it difficult to even describe the problem without anotion of the solution. It is wrong to expect developers do to a clean design and commit
to it at the start of this kind of problems. Experimentation, feedback, creativity areneeded.
Most systems development has the wrong basis. It supposes that the development process
is a well-understood approach that can be planned and estimated.
If a project fails, that is considered proof that the development process needs more rigor.
If we could consider developers to follow the process more rigorous the project can becompleted successfully.
But these step by step approaches don’t work, because they do not cope with theunpredictabilities (both human and technical) in system development.
At the start of neither a complete, detailed specification and planning of nor scheduling ispossible, because of these many uncertainties.
Developing systems is unpredictable and chaotic. Development is an empirical processthat requires significant thought during the process.
A method can only supply a framework for the real work and indicate the places where
creativity is needed. Yet we tread black-box processes often as fully defined processes.
Unpredictable results occur.
We lack the controls to measure and respond to the unpredictable.

While building a system many artifacts come into existence, many new insights are
gained. These new artifacts can guide future thinking.
Increased productivity through good tools or uncovered components may open theopportunity for adding more Backlog and more functionality to our system, or for
releasing a product early.
Customers and users can seldom give a final spec because their needs as constantly
evolving. The best they can do is evolve a product as their needs evolve and as they learn
along the process. In our development process we don’t use this learning cycle and its
benefits.
Developers and project managers often live (and are forced to) live a lie. They have topretend that they can plan, predict and deliver, and then work the best way that they know
to deliver the system. They build one way, pretend to build another way, and as a result
are without real controls.
Often overhead is created to proof that a process is on track.
We have followed Pert charts and the like, believing that a system would result.
Current process automation adds administrative work for managers and developers andresults often in marginally used development processes that become disk-ware.

Solution
Give the developers the space to be creative, and to learn exploring the design space,doing their actual work, undisturbed by outside interruptions, free to adapt their way ofworking using opportunities and insights. At the same time keep the management andstakeholders confident by showing real progress instead of documents and reports…
produced as proof. Do this in short cycles, Sprints, where part of the Backlog is allocatedto a small team. In a Sprint, during a period of approximately 30 days, an agreed amountof work will be performed, to create a deliverable. Backlog is assigned to Sprints bypriority and by approximation of what can be accomplished during a month. Chunks of
low cohesion and high coupling are selected. Focus is on enabling, rather than micromanagement.
During the Sprint outside chaos is not allowed in the increment. The team, as they
proceed, may change course and their way of working. By buffering them from theoutside, we allow them to focus on the work at hand and on delivering the best they canand the best way they can, using their skill, experience and creativity.
Each Sprint produces a visible and usable deliverable. This is demonstrated in
DemoAfterSprint. An increment can be either intermediate or shippable, but it should
stand on its own. The goal of a Sprint is to complete as much quality software as possible
and to ensure real progress, not paper milestones as alibi.
Sprints set up a safe environment and time slots where developers can work undisturbed
by outside requests or opportunities. They also offer a pre-allocated piece of work thatthe customer, management and the user can trust to get a useful deliverable such as aworking piece of code at the end of the Sprint. The team focuses on the right things todo, management working on eliminating what stands in the way of doing in better.

Rationale
Developers need time to work undisturbed, they need support for logistics andmanagement and users need to stay convinced that real progress is made.

ExamplesAt Argo, the Flemish department of education, we have been using Sprints since January
1997 on a large number of end-user-projects and for the development of a framework for
database, document management and workflow. The Backlog is divided in Sprints thatlast about a month. At the end of each Sprint a working Smalltalk image is delivered withintegration of all current applications. The team meets daily in Scrum Meetings andBacklog is allocated after the DemoAfterSprint in a monthly meeting with the steeringcommittee.

Resulting Context
High degree of effective ownership by all the participants (included users who stay
involved during the whole cycle, at least through demo’s and prioritizing Backlog).
At the end of a Sprint, we have the best approximation of what was planned at the start of
the Sprint. At the end of the Sprint, in a review session, the supervisors have theopportunity to change the planning for the future. The project is totally flexible at thispoint. Target, product, delivery date and cost can be refined.
With SCRUM we get a large amount of post-planning flexibility (for both customer anddeveloper).
During Sprints it may become clear, in the daily Scrum Meetings that some teammembers are loosing a lot of time at non- or less productive tasks. The high-visibility of
Scrum allows us to deal with this. During Scrum Meetings it may become clear thatpeople need more time for their tasks than originally allocated by management. Workers
may turn out less competent or experienced at the allocated task than assumed or they
may be in political or power struggles.
Difficulties in grouping backlog for a sprint may indicate that priorities are not clear to
management or to the customer.
The method is not suitable for people who need strong guidance; some people may
consider this way of working dangerous or insane.

Backlog
Context(FROM: )Your are anyone in a software, or any other project that is chaotic in nature needing
information on what to do next.

ProblemWhat is the best way to organize the work to be done next at any stage of the project?

Forces
Project plans captured in Pert charts or Gannt charts often try to capture the tasks to bedone a priori, but they often fail in their implementations, because they lack the flexibility
to change fast. Also these tasks are pre-allocated in time in Pert or Gant charts, but incontrast, their priorities and number grow of dimish as required in real projects.
Not having a repository of tasks in any shape or form simply translates into project
failure. There must be some sort of project control.

Solution
Use a Backlog to organize the work a SCRUM team.
The Backlog is a prioritized list. The highest priority backlog will be worked on first, thelowest priority backlog will be worked on last. No feature, addition, enhancement to a
product is worth fighting over; it is simply either more important or less important at any
time to the success and relevance of the product.
Backlog is the work to be performed on a product. Completion of the work willtransform the product from its current form into its vision. But in Scrum, the Backlog
evolves as the product and the environment into which it will be used evolves. So thebacklog is dynamic, constantly changed by management to ensure that the productdefined by completing the Backlog is the most appropriate, competitive, useful productpossible
There are many sources to the backlog list. Product marketing adds work that will fulfill
their vision of the product. Sales add work that will add new sales or extend theusefulness to the installed base. Technology adds work that will ensures the product fullyuses the most innovative and productive technology. Development adds work to enhance
product functions. Customer support adds work to correct underlying product defects.
Only one person prioritizes work. This person is responsible for meeting the productvision. The title usually is product manager, or product marketing manager. If anyone
wants the priority of work changed, they have to convince this person to change thatpriority. The highest priority backlog has the most definition. It is also prioritized withan eye toward dependencies.
Depending on how quickly products are needed in the marketplace and the finances ofthe organization, one or more Scrum teams work on a product’s backlog. As a Scrum
team is available (newly formed or just finished a Sprint) to work on the backlog, theteam meets with the product manager. Focusing on the highest priority backlog, the teamselects that Backlog that the team believes it can complete within a Sprint iteration (30days). In doing so, the Scrum team may alter the backlog priority by selecting backlog
that is mutually supportive, that is, that can be worked on at once more easily that
waiting. Examples are multiple work items that require developing a common module orinterface and that make sense to include in one Sprint.
The team selects a cohesive group of top priority Backlog, that – once completed – will
have reached an objective, or milestone. This is stated as the Sprint’s objective. During
the Sprint, the team is free to not do work as long as this objective is reached.
The team now decomposes the selected backlog into tasks. These tasks are discrete
pieces of work that various team members sign up to do. Tasks are performed tocomplete backlog to reach the Sprint objective.

Resulting Context
All tasks in the project are found dynamically and they are prioritized according to:
1) to the customer’s needs, and2) what the team can do.

4. Conclusions
Scrum is a knowledge creating process with a high level of information sharing during
the whole cycle and work progress.
Key to Scrum is pinning down the date at which we want completion for production orrelease, prioritizing functionality, identifying available resources and making majordecisions about architecture. Compared to more traditional methodologies the planningphase is kept short since we know that events will require changes to initial plans andmethods. Scrum uses an empirical approach to development where interaction with theenvironment is not only allowed but encouraged, changing scope, technology andfunctionality are expected and continuous information sharing and feedback keep
performance and trust high.
When combined together, SCRUM and other organizational patterns [OrgPatt], andspecially those by James O. Coplien [Coplien95], provide with an adaptive, yet wellstructured software development organization.
Their application also generates a strong culture that has well defined roles andrelationships, with meaningful and transcending rituals.

Acknowledgements
We would like to thank all of the SCRUM users and reviewers from which we received
feedback over the years. Also, we thank the all of the members of the Chicago Patterns
Group that attended an early review session of the Scrum Meeting pattern (especiallyBrad Appleton, Joe Seda and Bob Haugen). Finally we thank our PLOP98 shepherd,
Linda Rising, for providing us comments and guidance to make our paper better.
(Personal acknowledgement from Mike Beedle.) I’d like to thank both Jeff Sutherland
and Ken Schwaber for adapting the SCRUM techniques to software in the early 90s, andfor sharing with me their findings. SCRUM has made a significant contribution to thesoftware projects where I used the technique.

References[Goldratt90] E. Goldratt, Theory of Constraints, North River Press, Great Burlington(MA), 1990.
[Coplien95] J. Coplien and D. Schmidt, Pattern Languages of Program Design (AGenerative Development-Process Pattern Language), Addison and Wesley, Reading,
1995.
[Nonaka95] I. Nonaka and H. Takeuchi, The Knowledge Creating Company,
Oxford University Press, New York, 1995.
[OrgPatt] Org Patterns web site:
http://www.bell-labs.com/cgi-user/OrgPatterns/OrgPatterns?ProjectIndex[Schwaber97] K. Schwaber's, SCRUM web page:
http://www.controlchaos.com[Schwaber97-2] personal communication.
[Senge90] P. Senge, The Fifth Discipline - The art and Practice of the
Learning Organization, Doubleday/Currency, New York, 1990.
[Sutherland97] J. Sutherland, SCRUM web page:
http://www.tiac.net/users/jsuth/scrum/index.html
http://www.jeffsutherland.org/scrum/index.html[Weinberg97] G. Weinberg, Quality Software Management – Vol. 4., Anticipating
Change, Dorset House, New York, 1997.