Agile process

Agile Processes and Methodologies: A
Conceptual Study
Sheetal Sharma
Amity School of Engineering & Technology
Amity University Noida
Sheetal.meenu@gmail.com
Darothi Sarkar
darothisarkar@rediffmail.com
Divya Gupta
Fromdivya81@gmail.com
Abstract— This paper deals with the comparative study of agile processes. The paper will serve as guide to
other software development process models. Agile processes have important applications in the areas
of software project management, software schedule management, etc. In particular the aim of agile
processes is to satisfy the customer, faster development times with lower defects rate. This paper compares the
agile processes with other software development life cycle models. Agile processes are not always
advantageous, they have some drawbacks as well; the advantages and disadvantages of agile processes are
also discussed in this paper.
Keywords: Agile Development, Software Development Life Cycle (SDLC).
I. INTRODUCTION
In software development life cycle, there are two main considerations, one is to emphasize on process and the
other is the quality of the software and process itself. Agile software processes is an iterative and incremental
based development, where requirements are changeable according to customer needs. It helps in adaptive
planning, iterative development and time boxing. It is a theoretical framework that promotes foreseen interactions
throughout the development cycle. There are several SDLC models like spiral, waterfall, RAD which has their
own advantages. SDLC is a framework that describes the activities performed at each stage of a software
development life cycle[1]. The software development activities such as planning, analysis, design, coding,
testing and maintenance which need to be performed according to the demand of the customer. It depends on the
various applications to choose the specific model. In this paper, however, we will study the agile processes and its
methodologies. Agile process is itself a software development process[2]. Agile process is an iterative approach
in which customer satisfaction is at highest priority as the customer has direct involvement in evaluating the
software[3].
The agile process follows the software development life cycle which includes requirements gathering, analysis,
design , coding , testing and delivers partially implemented software and waits for the customer feedback. In the
whole process , customer satisfaction is at highest priority with faster development time. The following Figure. 1 ,
depicts the software development life cycle of Agile Process.
Sheetal Sharma et al. / International Journal on Computer Science and Engineering (IJCSE)
ISSN : 0975-3397 Vol. 4 No. 05 May 2012 892

Figure 1. Phases of Agile Process.
This paper is organized as follows: Characteristics of Agile processes are presented in section II. Section III
discusses the agile methodologies. Section IV discusses the advantages of Agile Process, Section V discusses the
disadvantages of Agile Process, Section VI discusses the comparison of Agile with other SDLC models. Finally,
conclusions are discussed in the section VII.
II. CHARACTERISTICS OF AGILE PROJECTS
Agile process requires less planning and it divides the tasks into small increments. Agile process is meant for
short term projects with an effort of team work that follows the software development life cycle. Software
development life cycle includes the following phases 1.Requirements gathering, 2.Analysis, 3.Design, 4.Coding
, 5.Testing, 6.Maintenance. The involvement of software team management with customers reduces the risks
associated with the software. This agile process is an iterative process in which changes can be made according to
the customer satisfaction. In agile process new features can be added easily by using multiple iterations.
1. Iterative
The main objective of agile software processes is satisfaction of customers, so it focuses on single
requirement with multiple iterations.
2. Modularity
Agile process decomposes the complete system into manageable pieces called modules. Modularity plays a
major role in software development processes.
3. Time Boxing
As agile process is iterative in nature, it requires the time limits on each module with respective cycle.
Requirement
gathering
Analysis
Design
Coding
Testing
Delivery of
partially
incremented
software
Feedback from
customer
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4. Parsimony
In agile processes parsimony is required to mitigate risks and achieve the goals by minimal number of
modules.
5. Incremental
As the agile process is iterative in nature, it requires the system to be developed in increments, each increment
is independent of others, and at last all increments are integrated into complete system.
6. Adaptive
Due to the iterative nature of agile process new risks may occurs. The adaptive characteristic of agile process
allows adapting the processes to attack the new risks and allows changes in the real time requirements.
7. Convergent
All the risks associated with each increment are convergent in agile process by using iterative and incremental
approach.
9. Collaborative
As agile process is modular in nature, it needs a good communication among software development team.
Different modules need to be integrated at the end of the software development process.
10. People Oriented
In the agile processes customer satisfaction is the first priority over the technology and process. A good
software development team increases the performance and productivity of the software.
III. METHODOLOGIES
There are several methodologies through which we can implement Agile Projects. Here we have discussed three
methodologies which are most widely used in Industry. The agile methods are focused on different aspects of
the software development life cycle. Some focus on the practices (extreme programming, pair programming),
while others focus on managing the software projects (the scrum approach).
A. Extreme Programming (XP)
XP is the most successful method of developing agile software because of its focus on customer satisfaction.
XP requires maximum customer interaction to develop the software. It divides the entire software development
life cycle into several number of short development cycles. It welcomes and incorporates changes or requirements
from the customers at any phase of the development life cycle.
Figure 2 : Method of Developing Agile Processes using Extreme Programming
Iteration
Planning
Project tracing
Development
(Iteration)
Iteration plan
User
Requirements
Priority
checking
Effort estimation
New user
requirements
Acceptance
testing
Latest developed
version
Release of the
latest version
Bug
New
requirementsRequirements
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The above diagram shows the complete method of developing agile process using XP method. Extreme
programming starts with collecting user requirements. Depending upon these requirements the whole
development process is divided into several small no of cycles. So the next phase is iteration planning i.e.
deciding the no of cycles, prioritizing the requirements and estimating the amount of effort required to implement
each cycle. Now each iteration is developed using pair programming. During the development phase new user
requirements may come and the iteration plan should be adjusted according to that. Next step is to test the latest
developed version for bugs, if detected; the bugs will be removed in the next iteration. After every acceptance
testing project tracing should be done in which feedback is taken from the project that how much job has already
been done.
XP has introduced many new things for developers like pair programming, extensive code review, code
refactoring and open workspace [4].
B. Scrum
Scrum is another popular method of agile development through which productivity becomes very high. It is
basically based on incremental software development process. In scrum method the entire development cycle is
divided into a series of iteration where each iteration is called as a sprint. Maximum duration of a sprint is 30
days.
Figure 3: Method of Developing Agile Processes using Scrum
The method starts with collecting user requirements but it is not expected that all the requirements should
come out from the user at the beginning. User can change their mind at any time during development; they can
add new features, remove or update some existing features. Next phase is to prioritize the requirements and the
list is known as product backlog [5]. A proper planning for sprint should be done i.e. how many sprints are
needed to develop the software, duration of the sprint, and what are the requirements from the product backlog
should be implemented in each sprint. This particular list is known as sprint backlog. During each sprint one
sprint meeting is held every day to take the feedback how much work has been done. After each sprint review is
taken to determine whether all the requirements for that particular sprint have already been implemented or not
and to decide the requirements should be implemented at the next sprint. After each sprint we get a working
increment of the software
C. Feature Driven Development (FDD)
FDD is one of the agile development methods. The key advantage of this method is to design the domain of
the software to be produced before development.
User
requirements Product
backlog
Planning of
sprint
Sprint
backlog
Sprint
Review of sprint
meeting
Latest increment
of the software
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Figure 4: Method of Developing Agile Processes using FDD Graph
The method starts with collecting the requirements from the users and building up the overall model of the
project. The model gives the clear idea about the scope of the software. Next step is to make a list of features
which are the client-valued functions [5]. For example ‘authenticate the password’, ‘calculate the salary for each
employee’, ‘calculate the income tax for each employee’. Now several groups of features are made based on their
domains i.e. related features are combined into a single group. Next step is to make a plan for developing the
features. Each group of features is assigned to a development team which is headed by one chief programmer.
Last step is modeling iteration in which first UML modeling is done for each feature and then developing that
particular feature. This step continues unless all the features get implemented successfully.
IV. ADVANTAGES
1) Adaptive to the changing environment: In agile software development method, software is developed
over several iterations. Each iteration is characterized by analysis, design, implementation and testing. After
each iteration the mini project is delivered to the customer for their use and feedback. Any changes that upgrade
the software are welcome from the customer at any stage of development and that changes are implemented.
2) Ensures customer satisfaction: This methodology requires active customer involvement throughout the
developmen[6]t. The deliverables developed after each iteration is given to the user for use and improvement is
done based on the customer feedback only. So at the end what we get as the final product is of high quality and
it ensures the customer satisfaction as the entire software is developed based on the requirements taken from
customer.
3) Least documentation: The documentation in agile methodology is short and to the point though it
depends on the agile team. Generally they don’t make documentation on internal design of the software. The
main things which should be on the documentation are product features list, duration for each iteration and date.
This brief documentation saves time of development and deliver the project in least possible time.
User
requirements
Developing
overall model
Preparing list of
features
Planning by
features
Modeling
iteration
Designing UML
model for each
feature
Developing by
features
Successful and
properly developed
feature
Modeling iteration
Complete
working
software
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4) Reduces risks of development: As the incremented mini software is delivered to the customers after
every short development cycle and feedbacks are taken from the customers, it warns developers about the
upcoming problems which may occur at the later stages of development. It also helps to discover errors quickly
and they are fixed immediately.
V. DISADVANTAGES
1) Customer interaction is the key factor of developing successful software: Agile methodology is based
on customer involvement because the entire project is developed according to the requirements given by the
customers. So if the customer representative is not clear about the product features, the development process
will go out of the track.
2) Lack of documentation: Though the least documentation saves development time as an advantage of
agile method, on the other hand it is a big disadvantage for developer. Here the internal design is getting
changed again and again depending on user requirements after every iteration, so it is not possible to maintain
the detail documentation of design and implementation because of project deadline[7]. So because of less
available information, it is very difficult for the new developers who join the development team at the later stage
to understand the actual method followed to develop the software.
3) Time consuming and wastage of resources because of constant change of requirements: If the
customers are not satisfied by the partial software developed by certain iteration and they change their
requirements then that incremented part is of no use. So it is the total wastage of time, effort and resources
required to develop that increment.
4) More helpful for management than developer: The agile methodology helps management to take
decisions about the software development, set goals for developers and fix the deadline for them. But it is very
difficult for the baseline developers to cope up with the ever changing environment and every time changing the
design, code based on just in time requirements.
VI. COMPARISON OF AGILE PROCESS WITH OTHER SDLC MODELS
TABLE I. PRCOESS MODELS
Features
Different Process Models
Agile Process Spiral Model RAD Model
Definition
Agile process is the ability to both
create and respond to changing
requirements of software.
Spiral model is the
software development
model which focuses on
managing risks.
RAD model is “high speed
adaptation of linear sequential
model, in which component
based construction is used.
Adaptability   X
Testing Phase Unit, Integration , System testing
Unit, Integration and
System testing
Unit
Quality Factors   X
Risk Analysis X  X
Off-the- Tools X X 
Failure normally due to Code Code Architecture and design
Knowledge Required Product and domain Product and domain Domain
Entry & exit Criteria X X 
Mock up   X
Extendability   X
Project management involvement  X 
Higher Reliability   X
Time Boxing  X 
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Features
Different Process Models
Agile Process Spiral Model RAD Model
Status of Development Team Less experience required Less experience required More experience required
Use of reusable components X X 
Flexibility   X
Customer Involvement   X
VII. CONCLUSION
In this paper we have discussed the software development life cycle models, the characteristics of agile
process, and spiral model, methodologies of agile process, advantages and disadvantages. In the comparative
study of agile software development with other software development models we conclude that agile project is
much better than other software development process in terms of productivity, performance, faster time cycles,
risk analysis. Agile processes are implemented in important applications such as web based, testing tools, etc.
REFERENCES
[1] Tobin J Lehman, Akhilesh Sharma , “Software Development as a service: Agile Experiences”, in annual SRII Global
Conference (2011).
[2] A. Ahmed, S. Ahmad, Dr. N Ehsan, E. Mirza, S.Z. Sarwar,“Agile Software Development: Impact on Productivity and Qulaity”,
in the Proceedings of IEEE ICMIT.(2010).
[3] B.Boehm and R.Turner, “Balancing Agility and Discipline: A Guide for the Perplexed, Addison, Wesley, 2003.
[4] Jeffery A. Livermore, “Factors that Impact Implementing an Agile Software Development Methodology” in the Proceedings of
IEEE (2007)
[5] http://en.wikipedia.org/wiki/Scrum_(development)
[6] B.Boehm, “ Anchoring the Software Process,” IEEE Software, July 1996.
[7] B. Boehm and D.Port,”Balancing Discipline and Flexibility with the Spiral Model and MBASE”. Crosstalk, Dec. 2001.
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Agile process

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