SCRUM is an Organization Pattern
From: Michael A. Beedle
Date: Wednesday, December 03, 1997 1:01PM
To: Organization Patterns (e-mail)
Subject: SCRUM Revisited
You are engaged in an activity that is difficult
to control because its predictability is limited. For example, the
activity may require constant change in directions, it may add new tasks
as it unfolds, or it may require unforeseen interactions with many participants.
Activities such as scientific research,
innovation, invention, architecture, engineering of any kind and software
development typically exhibit such behavior common to "creative tasks".
As such, you may be a "knowledge worker",
and engineer, a writer, a research scientist, a software developer or an
artist; or a coach or leader that is overseeing the activities of a team
such as a Coach, a Team Leader, a ScrumMaster, a Manager or a Firewall
in a development team, etc. (From: Case Team,
Developer Controls Process [OrgPatt])
What is the best way to control an empirical
process such as software development, scientific
projects or innovative designs?
Project plans in medium to large software projects
because estimates for assignments are hard
to come up with. (There are
many sources for this uncertainties, for
example: 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.)
Estimation is important. One must be able
to determine what are the future tasks within some time horizon.
Planning and reprioritizing tasks take time.
Using too much of the knowledge workers' time in planning meeting deceases
Architectural management leading to reusability
Delivery of Customer driven software units such
as Use Cases, must be driven to completion.
Meet with the team members for a short time
in a daily SCRUM meeting. A SCRUM meeting is a 15. minutes meeting
where each participant only answers the following 3 questions:
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 team members choosing the appropriate
tasks to work on with the help of the Architect. Because the tasks
are schedule in a 24 hr basis the tasks are typically small (Small Assignments).
The SCRUM meetings typically take place at
the same time and place every day. The ScrumMaster leads the meetings
and he logs all the tasks from every member of the team into a global project
Backlog. He also logs every Block and he resolves each Block while
the developers work on the new
SCRUMs can also be held by self-directed
teams, in that case someone is designated as the scribe and also 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
the team members for resolution.
The format of the Backlog and the Blocks
can also vary, ranging from a list of items on a piece of paper all the
way through software implementations over the INTERNET/INTRANET [Schwaber97].
The Scrum cycle can be adjusted according to needs but typically does not
exceed the 48 hr. cycle or decreasing lower than 2 hrs.
SCRUM meetings not only schedule tasks for
the developers but can and should schedule activities for everyone involved
in the project such as integration personal dedicated to configuration
management, architects, ScrumMasters (Firewall/Coach), etc.
Scrum meetings allow knowledge workers to
accomplish mid-term goals typically allocated in Sprints that last for
about a month.
Because it is very easy to under- or over- shoot
an estimate, that either leads to idle developer's time or to delays in
the completion of an assignments respectively, it is better to sample frequently
the status of small assignments. In other words, 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
on 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":
Simultaneously, this same mechanism, encourages
the team members to socialize, externalize, internalize and combine technical
knowledge on an ongoing basis, thus allowing technical expertise to become
"community property" for the community of practice [Nonaka95]. SCRUM
is therefore a ritual with a deep cultural transcendence.
increase the overall sense of urgency,
promote the sharing of knowledge,
encourage dense communications and
facilitate "honesty" among developers i.e. everyone
has to give a daily status.
Seen from the System Dynamics point of view
[Senge94], software development has "scheduling" 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 the estimates
2) there are typically interlocking architectural
dependencies that are hard to manage
3) there are unknown or poorly documented
4) there are unforeseen technical challenges
And 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 SCRUM meeting
become the equivalent of a "thermometer" that constantly sample the new
team temperature [Schwaber97-2].
At Nike Securities in Chicago we are using SCRUM
meetings since February of 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.
A structure such as Case Team or Developer Controls
Process (using Form Follows Function) is
jelled into a highly adaptable and
hyperproductive team structure.
[Goldratt90] E. Goldratt, Theory of Constraints,
North River Press, Great Burlington (MA), 1990.
[Nonaka95] I. Nonaka and H. Takeuchi, The
Knowledge Creating Company, Oxford University Press, New York, 1995.
[OrgPatt] Org Patterns web site
[Schwaber97] K. Schwaber's, SCRUM web page,
[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
[Weinberg97] G. Weinberg, Quality Software
Management - Vol 4., Anticipating Change. Dorset House, New York, 1997.
Other SCRUM patterns (not included here)
- ScrumMaster (FireWall, Coach), Sprints, Backlog (Queue of Work), Small
Assignments, Pigs and Chickens, etc.
© Jeff Sutherland 1995-98