Filetype PDF | Posted on 30 Jan 2023 | 2 years ago
Authentication
digital resources
151x Filetype PDF File size 0.22 MB Source: sunnyday.mit.edu
SOFTWARE MANAGEMENT
them is the only viable strategy. Rather
than eliminating rework, the new strat-
Agile Software egy is to reduce its cost.
However, in not just accommodating
change, but embracing it, we also must
be careful to retain quality. Expectations
Development: have grown over the years. The market
demands and expects innovative, high-
quality software that meets its needs—
The Business of and soon.
THE AGILE RESPONSE
Agile methods are a response to this
expectation. Their strategy is to reduce the
Innovation cost of change throughout a project.
Extreme Programming (XP), for example,
Jim Highsmith, Cutter Consortium calls for the software development team to
Alistair Cockburn, Humans and Technology • produce the first delivery in weeks,
to achieve an early win and rapid
feedback;
he rise and fall of the dot- change grows through the software’s • invent simple solutions, so there is
com-driven Internet economy development life cycle—remains valid, less to change and making those
shouldn’t distract us from see- the question today is not how to stop changes is easier;
Ting that the business environ- change early in a project but how to bet- • improve design quality continually,
ment continues to change at a ter handle inevitable changes throughout making the next story less costly to
dramatically increasing pace. To thrive its life cycle. implement; and
in this turbulent environment, we must
confront the business need for relentless
innovation and forge the future work- Agile development combines
force culture. Agile software develop-
ment approaches such as Extreme Pro- creative teamwork with an
gramming, Crystal methods, Lean intense focus on effectiveness
Development, Scrum, Adaptive Software
Development (ASD), and others view and maneuverability.
change from a perspective that mirrors
today’s turbulent business and technol-
ogy environment.
Traditional approaches assumed that if • test constantly, for earlier, less
THE PROBLEM we just tried hard enough, we could antic- expensive, defect detection.
In a recent study of more than 200 ipate the complete set of requirements
software development projects, QSM early and reduce cost by eliminating Agile software development stresses
Associates’ Michael Mah reported that change. Today, eliminating change early quality in design. These methods are some-
the researchers couldn’t find nearly half means being unresponsive to business con- times confused with ad hoc or cowboy
of the projects’ original plans to measure ditions—in other words, business failure. coding because the design is done on an
against. Why? Conforming to plan was Similarly, traditional process manage- ongoing basis, in smaller chunks, as
no longer the primary goal; instead, sat- ment—by continuous measurement, opposed to all at once and up front. Each
isfying customers—at the time of deliv- error identification, and process refine- agile method addresses quality in certain
ery, not at project initiation—took ments—strove to drive variations out of ways. For example, Dynamic Systems
precedence. In many projects we review, processes. This approach assumes that Development Methodology (DSDM) calls
major changes in the requirements, variations are the result of errors. Today, for a series of prototypes to attack unsta-
scope, and technology that are outside while process problems certainly cause ble or unknown areas: new technology,
the development team’s control often some errors, external environmental new business rules, and user interface
occur within a project’s life span. changes cause critical variations. Because design. Scrum uses intense 15-minute daily
Accepting that Barry Boehm’s life cycle we cannot eliminate these changes, dri- meetings and comprehensive iteration
cost differentials theory—the cost of ving down the cost of responding to reviews at the end of each 30-day iteration.
120 Computer
Basic principles must give, and we need to be clear about when a team of individuals practices
Agile methods stress two concepts: the what stays and what gives. them.
unforgiving honesty of working code and Relying on interactions between indi- Most methodologies provide inclusive
the effectiveness of people working viduals facilitates sharing information rules—all the things you could possibly
together with goodwill. and changing the process quickly when it do under all situations. Agile methods
Working code tells the developers and needs changing. Using working software offer generative rules—a minimum set of
sponsors what they really have in front allows us to measure how fast we actu- things you must do under all situations to
of them—as opposed to promises as to ally produce results and provides quick generate appropriate practices for special
what they willhave in front of them. The feedback. Frequent interaction between situations. Teams that follow inclusive
working code can be shipped, modified, individuals compensates for minimizing rules depend on someone else to name in
or scrapped, but it is always real. documentation. advance the practices and conditions for
Using people effectively achieves every situation. This obviously breaks
maneuverability, speed, and cost savings. down quickly. A team that follows gen-
People can transfer ideas faster by talking In a complex adaptive erative rules depends on individuals and
face to face than by writing and reading system, decentralized, their creativity to find ways to solve prob-
documents. A few designers sitting independent individuals lems as they arise. Creativity, not volu-
together can produce a better design than interact to create minous written rules, is the only way to
each could produce alone. When devel- innovative, emergent manage complex software development
opers talk with customers and sponsors, results. problems and diverse situations.
they can iron out difficulties, adjust pri-
orities, and examine alternate paths for- AGILE PRACTICES
ward in ways not possible when they are A team isn’t agile if the feedback loop
not working together. Customer collaboration means that with customers and management is six
all players—the sponsor, customer, user, months. Agile approaches recommend
Agile Software Manifesto and developer—are on the same team. short iterations in the two- to six-week
In recognition of these ideas, in Febru- Merging their different experiences and range during which the team makes con-
ary 2001, we joined 15 other people rep- expertise with goodwill allows the com- stant trade-off decisions and adjusts to
resenting XP, Scrum, DSDM, ASD, bined group to change directions new information. XP and Scrum have
Crystal, Feature-Driven Development, quickly so they can produce more more directed cycles—two to three weeks
pragmatic programming, and others appropriate results and less expensive for XP, 30 days for Scrum; other meth-
sympathetic to the need for alternative designs. Contracts or project charters ods such as Crystal and ASD tolerate
software development methods in sign- with the customers are necessary, but more variation.
ing the Manifesto for Agile Software without collaboration, they are insuffi-
Development. We wrote: cient. Feature planning and
Working through producing a plan dynamic prioritization
We are uncovering better ways of drives the team members to think Agile approaches combine these short
developing software by doing it and through their project and its contingen- iterative cycles with feature planning and
helping others do it. Through this cies. The plan itself usually goes out of dynamic prioritization. XP uses story
work we have come to value date within just a few days. Afterward, cards; Scrum uses the term “backlog”;
rather than focusing on the outdated ASD and Feature-Driven Development
• individuals and interactions over plan, it is important to deal with the refer to features. The key point is that
processes and tools, changing realities. agile approaches plan features, not tasks,
• working software over comprehen- as the first priority because features are
sive documentation, GENERATIVE RULES what customers understand.
• customer collaboration over One aspect of agile development is Dynamic prioritization means that at
contract negotiation, often missed or glossed over: a world the end of an iteration, the customer can
• responding to change over follow- view that organizations are complex reprioritize the features desired in the
ing a plan. adaptive systems. A complex adaptive next cycle, discarding originally planned
system is one in which decentralized, features and adding new ones. Scrum
That is, while there is value in the items independent individuals interact in self- explicitly states that priorities can only
on the right, we value the items on the organizing ways, guided by a set of sim- change at the end of an iteration, not dur-
left more. ple, generative rules, to create inno- ing one. DSDM uses “MoSCoW” rules
vative, emergent results. XP’s 12 prac- for features—Must have, Should have,
Processes, tools, documentation, contracts, tices, for example, were never intended Could have, Want to have sometime.
and plans are useful. But when push comes to be all-inclusive rules; instead, they are XP’s priority scheme is binary—in this
to shove—and it usually does—something generative rules that interact in concert cycle, or not.
September 2001 121
Software Management
Feedback and change Agility is dynamic, context-specific,
Because they are most applicable to tur- aggressively change embracing, and
bulent, high-change environments, agile growth-oriented. It is not about improv-
Next- approaches recommend a variety of prac- ing efficiency, cutting costs, or batten-
tices for constant feedback on technical ing down the business hatches to ride
decisions, customer requirements, and out fearsome competitive “storms.” It is
management constraints. XP advocates about succeeding and about winning:
generation pair programming for feedback, and about succeeding in emerging compet-
DSDM features short-cycle user proto- itive arenas, and about winning profits,
typing. Crystal and ASD advocate end-of- market share, and customers in the very
iteration process and team reviews. ASD center of the competitive storms many
courses and Scrum use end-of-iteration reviews companies now fear.
with customer focus groups.
for the Agile practices encourage change This book was about manufacturing, but
rather than discourage it. In turbulent the definition of agility applies equally to
business situations, a methodology’s today’s software development environ-
next change tolerance must be geared to the ment.
change rate of a specific environment, not Agility, ultimately, is about creating
some internal view of how much change and responding to change. What is new
generation is acceptable. For example, changes to about agile methods is not the practices
feature priorities and requirements are they use, but their recognition of people
of computer handled within the context of a team and as the primary drivers of project success,
the customer partners unless the changes coupled with an intense focus on effec-
violate the broad scope, schedule, and tiveness and maneuverability. This yields
professionals cost constraints set by the purchasing a new combination of values and princi-
customer (or management). ples that define an “agile” world view.
Agile software development addresses
Influence what our Focus on teamwork two pressures that characterize today’s
Team proximity and intense interac- business and technology world: the need
students learn. tion between team members are hall- for dynamic, innovative approaches and
marks of all agile methods. XP is noted the desire to build workplaces that aren’t
for pair programming, although the prac- described in Dilbert cartoons. ✸
tice has been around for years under
Review the latest draft of other names. Crystal, Scrum, and ASD
Computing Curricula 2001. advocate close collaboration practices
including barrier-free collocated teams.
Lean Development stresses team interac- Jim Highsmithis director of Cutter Con-
http://computer.org/ tion. sortium’s e-Project Management Prac-
education/curricula2001 Using agile development methods tice. Contact him at jimh@adaptivesd.
requires close customer partnerships. If com.
the customers, either internal department
Prepared by the representatives or marketing product
managers, don’t have a good sense of
IEEE Computer Society/ direction and wander around in strange
ACM joint task force on patterns, agile developers will follow Alistair Cockburnis a Consulting Fellow
them (with occasional admonitions, of at Humans and Technology. Contact him
Computing Curricula 2001 course). Poor customers result in poor at arc@acm.org.
systems.
n 1995, Steven L. Goldman, Roger N.
Nagel, and Kenneth Preiss, the Editor: Barry Boehm, Computer Science
I authors of Agile Competitors and Department, University of Southern Califor-
Virtual Organizations (Van Nostrand nia, Los Angeles, CA 90089; boehm@
Reinhold, New York), offered this defin- sunset.usc.edu
ition of agility:
122 Computer
no reviews yet
Please Login to review.
