Agile (adaptive) model
Written by Marco Lombardo s210384
Agile model is a new way of riding the development approach and the life cycle performance domain of a Project, Program and Portfolio Management (PPPM). The focus of the model is on process adaptability and customer satisfaction. The model is based on iterative and incremental processes combined to achieve a rapid delivery of working software product. 
Although there are some adaptive methods dating back to before 2000’s, it is possible to date the concept of agile in 2001, when it was signed the “Agile Manifesto”. The Agile Manifesto outlines four Core Values (individuals and interactions; working software; customer collaboration; and responding to change) and twelve Guiding Principles which are of key importance for any team aiming at using an agile model.
The agile model is an adaptive model that uses iterations called also sprints to divide the project life cycle to work with a short-term planning. It is possible to define each sprint as the sum of 5 phases: gathering, design, construction, testing, close, and after each iteration the teams receive feedback,  whereas the traditional models are based on a predictive approach (e.g., waterfall model). Both typologies of modelling have their pros and cons and the best approach to follow depends on the project/product.
The goal of the agile model is to assist companies in providing value more frequently to their clients, reacting quicker to changes, and eventually improving the business.  It is utilized when it is necessary to divide a large project into more reasonable tasks and complete them in short iterations throughout the project life cycle, defined as the set of phases from the start to the end of a project.
The model can be applied to almost any project, but for high complexity of design and scale of projects, companies prefer to use the predictive models. It is also important that the companies adopting the agile model make sure that their employees are aware of the rules and methodologies to successfully work with such a model.
Keywords: development approach, agile model, adaptive, sprint, PPPM
The development approaches are tools that allow people to correctly follow the steps to create software that meets a business need. It is possible to divide the development approaches in two big areas, adaptive and predictive approaches; the agile model is a tool based on the adaptive approach. This model is used for its elasticity and adaptability and based on an iterative approach.  It is possible to define the agile model as a lightweight method compared with all the other development models.
The Agile Manifesto was written in 2001, when 17 developers in Wasatch Mountains (Utah) had a meeting focused on the technological development of the future. Everyone agreed to the fact that most companies were drowning in documentation and were focusing too much on planning, with the consequence that they were losing what was the most important thing for their business: their clients.
For this reason, that weekend they wrote a short document (with only 68 words) that changed completely the development of software and the way of working for big companies. The idea of the Agile Manifesto was to find a common area among the most used frameworks conceptually close to the agile method (for example: Scrum, Extreme Programming, Kanban and other frameworks).
“The Agile Manifesto has four Core Values:
- Individuals and interactions over processes and tools
- Working software over comprehensive documentation
- Customer collaboration over contract negotiation
- Responding to change over following a plan." 
The twelve principles are the conceptualization of how teams and companies need to work if they want to follow the agile model.
The model is based on high priority of customer satisfaction; in order to achieve this, the people involved in the project need to share the deliveries of each iteration with the other team members and with the clients, in order to keep a high relation between them and, at the same time, if there is a need to make changes in the project, it is possible to do so even if the project is in the final stage of development. The reason why it is possible to have such a flexibility is that all the timelines are organized in order to have a short timescale, and all the deliveries are set within a time schedule ranging from two weeks to a couple of months. All the teams working on the project should work together having daily meetings, because the development of an agile project is based on trust between teams and companies. In fact, it is important that everyone is supported and motivated, keeping a good environment and giving people high motivation. Transparency and face to face conversation are the base to gather all the information needed to design the whole project. The agile model is based on software which reduces the weight of the tasks, and thanks to which it is possible to measure the daily progress. The processes of the agile model promote the sustainable development, and everyone involved shall respect the environment and the work done individually. The agility gives the possibility to have good design and excellent technical procedures thanks to the continuous attention of details. Having a very organized teamwork and individuals help designing the best architecture fulfilling the requirements. After each iteration, the teams share their ideas on how to be more effective. 
Sprints of the agile model
The model is well defined using the word adaptive and it is used in companies to break projects in small pieces. The approach used is that there is no detailed planning of long-term work; it is possible to have a clear idea of future tasks only when these tasks will be necessary to be developed. Using this method, the teams need to be elastic and able to easily adapt when the product requirement is changing. The particularity of the agile model is that a product is examined continuously using iterations, minimizing on this manner the uncertainty on the final goal. The iterations involve different teams that simultaneously work on various areas.  The work done in every working session is also known as sprints. The sprints have variable durations that can range from few days to few weeks. The idea is to have a rotating release schedule from the teams to demonstrate that these segments are working well and, if not, to quickly fix any flaws.
The agile model consists of 5 main phases:
- Gathering: this is the starting point for each project. The first phase is important because there is the need to make a plan in order to conceptualize the product and the needs of the end customer, and also understand who the stakeholders are, and which of the teams will be interested in the project.
- Design: this phase is important to create the initial requirements for the product. The idea is to encourage each team involved in the project to have a holistic view and explore different ideas for the project. It is the phase that expand the collaboration of the team members. It is important because teams need to have a good overview of the product and also of the timeline for the deliveries.
- Construction: this phase is focusing on deliveries and particularly on the requirements and the constraints that the teams should follow. It is important to have a good collaboration between teams and a good interaction with customers and stakeholders.
- Testing: in this phase teams analyse the results with what was planned. Teams can adapt or make changes in order to have a better product. The most important work is to receive and elaborate feedback.
- Close: the iteration is finished; each team should share the results and receive feedback from the customer in order to start the new iteration.  The most important thing to do in this phase is to analyse all the key-points of the project and save all the knowledge gathered.
Overall, agile is about adaptive planning, getting earlier deliveries and ensuring a steady improvement throughout every sprint. Key concepts to realize this are rapid response and adaptation to change. 
Adaptive (agile model) vs. predictive (waterfall model)
To explain where an agile model can be applied, it is important to understand the differences between adaptive (agile model) and predictive (waterfall model) methodologies.
A development approach is the method utilized to design and develop product, service, or the resource involved in the life cycle of a project. Each project is different compared to another, and the approach used can change considering the complexity and volatility of it. In fact, companies with projects with a high complexity are the ones which prefer working using a predictive model, while the ones with projects with a high volatility prefer the adaptive model. 
The adaptive strategies change exactly as fast as the real constraints and idea might change; for this reason, this approach is very useful when the requirements to develop a product have a high level of uncertainty and there can be changes during the project. The model defines a clear vision of the full project in the early phase. The development of the project is based on the user feedback, and all changes are done in accordance with the stakeholders. Usually, the method utilizes iterative and incremental approaches with a duration from one to two weeks and where each team involved in the project should deliver and share with the other teams the work done. 
Predictive approaches, in contrast, are utilized when it is possible to identify, gather and analyse the requirements before the starting point of a project life cycle to reduce as much as possible the changes and replanning the phases of a project. This method, in fact, is useful because it reduces the uncertainty related with the risk management of the project and for this reason it is used when the investment is important. 
The predictive models, in particular the waterfall model, are still the most used to manage projects. They are defined also as linear sequential models. Often, it is possible to consider the waterfall model as the traditional approach to project management. It is organized in a strict way of planning and executing the plan step-by-step, and each step is dependent on the previous. This type of linear approach cannot be useful if the product needs dynamic and fast changing environment, as more and more common nowadays. In a waterfall project, if there is a need to fix a failure it will require lots of extra time and cost, that are not planned with the clients. For this reason, many companies are strict to ensure that projects satisfy the constraints before continuing to the next phase, otherwise it will have to be rebuilt from the starting point.
Considering that, it is possible to make a clear line in between the two methodologies and to try to understand when it is better one and when the other.
The waterfall model is suitable for projects with well-defined requirements, where almost no changes are expected. Instead, agile works smoothly when there is a higher chance of frequent requirement changes. Agile is a flexible model able to adapt to the change of requirements, also if it will happen daily. Instead, in the waterfall model the constraints are defined with the business analyst only once at the starting point of the project. 
Companies which adopted the agile model
The agile model is an uncommon method and sometimes a challenge for big companies, because it requires strong ability of the teams, flexibility, and fast response to changes; something that does not seem to be compatible with the rigid structures of large companies. But there are some big companies like CISCO (IT), Lego (IT), Barclays (Finance), Panera Bread (IT), Ericsson (Mobile network), PlayStation (Gaming), John Deere (IT), Fitbit (technology), OpenLink (Finance), Royal Philips (medical technology company) which adopted the agile model and they got positive results from it. 
Examples of agile software
Some examples of the most popular agile methods are:
- Scrum: The first agile framework is Scrum, which uses iterative and incremental frameworks and daily meetings (also known as Scrum ceremonies) at intervals in order to facilitate the development and the performance of the teams in the life cycle of a project. The method offers benefits such as security, quality, and decreasing of the project cost thanks to the combination of iterative and incremental approaches called sprints. The first step is to set the goals of each sprint; according to this framework, it is not possible to modify the focus of the sprint, but it is possible to increase the number of sprints and/or modify the scope of one of the future ones. The three important roles in Scrum are: the leader of a project is usually the Scrum master, the client is the product owner, while the people developing the product are the scrum team members. 
- Kanban: The Kanban method is one of the most used frameworks which consists of the visual workflow, and presentations showing all the tasks of the project. Each task is displayed in a kanban board where the team members can see the state of every piece and work on that at any time. The system helps to eliminate waste focusing on the costumer's value. The core of Kanban is visualizing the workflow, limit WIP (work in progress) and measure the lead time. 
- Extreme programming (XP): The last model is the Extreme programming, an agile software development framework based on supporting teams who are working with continuous changes in the project, producing a higher quality software and quality of work thanks to the management of codes. The model is the most specific among all agile frameworks for what concerns good engineering practices for developing software and matching the requirements of the users. The values of the extreme programming are four: communication, simplicity, feedback, courage. 
Limitations - Pros and Cons
In the last decades, agile methods are becoming more and more accepted in the software world. However, there are some cases in which these methods may not be suitable. As shown below, the agile model presents many advantages, but has also a number of disadvantages to be taken into consideration.
The pros of agile model are many. First, the model is based on transparency and great collaboration between teams and not only, in fact, it a creates a strong relationship between clients and the developing team. This is done thanks to the continuous delivery of a workable product which increases the customer satisfaction. Secondly, the functionality of the model is meant to be developed quickly by cutting overall development time (the deliveres of software are reduced at 1-2 weeks) and to be demonstrated; its adaptability makes it suitable both for fixed or changing requirements and the resource requirements are minimum. With regards to the types of teams it can be applied to, the model suits in a good team environment and improves the teamwork and cross training. Moreover, the agile model provides early partial working solutions, minimal rules, easily employed documentation. It is a good model for environments that are continuously changing and evolving, as it improves flexibility to developers, and it is easy to manage. Lastly, it requires very little planning, enables concurrent development and delivery within an overall planned context. 
However, the agile method is not optimal for all cases. Even though the principles of the model are meant to resolve some of the drawbacks that could arise from using the waterfall approach, it is not uncommon that companies and/or organizations do not achieve the expected advantages. This is due to at least one of the following reasons. 
In the first place, it is not suitable for handling complex dependencies, as it might pose more risk of sustainability, maintainability, and extensibility of the product, if this is too complex and it is hard and difficult to measure how much effort will be needed to start the life cycle of a larger project. Moreover, the model cannot be used by all companies because it requires a certain structure and guidelines to be in place: an overall plan, an agile leader and an agile project manager are a must, without which it will not work. For the successful implementation of the model, it is fundamental that all deliveries and deadlines are strictly managed, as they dictate the scope and guarantee the correct sequence of functionalities to be delivered. Additionally, there could be some misunderstanding among groups due to the fact the documentation is not explained well or because of a lack of emphasis and it is able to result in hard transitions among phases. Moreover, the model depends heavily on customer interaction, so if the customer is not clear or does not have well-defined goals, the team can be driven in the wrong direction or if the client and the team are in different pages the project will derail. For large companies, it could be a disadvantage to use the agile model due to the fact that it entails a very high individual dependency, since it generates minimum documentation. Due to this lack of documentation, the transfer of technology to new team members may be quite challenging; this means that an agile model requires senior developers and there is no space for people without good knowledge of programming skills.  Sometimes, the structure of a project becomes too complex forcing the companies to follow the waterfall model. This happens because the teams involved have not enough knowledge of how the model works or due to the fact that there is not any kind of system design.
To conclude, the agile model represents a good method when it is more important the speed of creating a product compared to its eminence. It is also proven to be useful in the cases where clients are often changing the scope of the project and when the idea to be achieved is not fully defined. From the point of view of the human resources of the companies, good skilled, independent, and adaptable developers are key. Lastly, it is recommended to use the agile model if the industry has to fulfil the continuously varying standards. 
A Guide to the Project Management Body of Knowledge (PMBOK ® Guide) – 7th Edition and The Standard for Project Management, Project Management Institute, Inc., 14 Campus Boulevard, Newtown Square, Pennsylvania 19073-3299 USA, 2021 ISBN: 978-1-62825-664-2
- This modern guide enables project team members to be proactive, innovative, and nimble in delivering project outcomes. Chapter 2, Project Performance Domains, explains the differences between adaptive and predictive methods and when they should be used.
Hunt, J. (2006). Agile software construction. Agile Software Construction (pp. 1–254). Springer London. https://doi.org/10.1007/1-84628-262-4
- This book explains in a realistic way how the different methods can work together, it is a very good book to have more knowledge on the agile method and its framework.
A. Srivastava, S. Bhardwaj and S. Saraswat, "SCRUM model for agile methodology," 2017 International Conference on Computing, Communication and Automation (ICCCA), 2017, pp. 864-869, doi: 10.1109/CCAA.2017.8229928.
- This is a good article which explains the uses of the Scrum model
Z. Bougroun, A. Zeaaraoui and T. Bouchentouf, "The projection of the specific practices of the third level of CMMI model in agile methods: Scrum, XP and Kanban," 2014 Third IEEE International Colloquium in Information Science and Technology (CIST), 2014, pp. 174-179, doi: 10.1109/CIST.2014.7016614.
- This document gives a presentation of the CMMI model and Scrum, XP, and Kanban methods
- ↑ 1.0 1.1 1.2 1.3 SDLC - Agile Model https://www.tutorialspoint.com/sdlc/sdlc_agile_model.htm
- ↑ Sharma, Sheetal & Sarkar, Darothi & Gupta, Divya. (2012). Agile Processes and Methodologies: A Conceptual Study. International Journal on Computer Science and Engineering. 4. https://www.researchgate.net/publication/267706023_Agile_Processes_and_Methodologies_A_Conceptual_Study
- ↑ Agile Body of Knowledge https://kanbanize.com/agile
- ↑ 4.0 4.1 COMPARATIVE STUDY: WATERFALL V/S AGILE MODEL, A. Dubey, A. Jain, A. Mantri, Acropolis Institute of Technology and Research, Indore (M.P), India, March, 2015 http://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=F2BCA87C0B147D28CC78CED89B3802CC?doi=10.1.1.695.9278&rep=rep1&type=pdf]
- ↑ 5.0 5.1 Manifesto for Agile Software Development, 2001 http://agilemanifesto.org
- ↑ Agile model software engineering https://www.javatpoint.com/software-engineering-agile-model
- ↑ 7.0 7.1 Introduction to agile and waterfall https://www.blueoceanworkshops.com/agile-adaptive-vs-waterfall-predictive-project-management/
- ↑ 8.0 8.1 8.2 Project Management Institute, Inc. (PMI). (2021). A Guide to the Project Management Body of Knowledge (PMBOK ® Guide) – 7th Edition and The Standard for Project Management. Project Management Institute, Inc. (PMI). Retrieved from https://app.knovel.com/hotlink/toc/id:kpSPMAGPMP/guide-project-management/guide-project-management
- ↑ 10 companies killing it at scaling agile,Christopher Null https://techbeacon.com/app-dev-testing/10-companies-killing-it-scaling-agile
- ↑ A. Srivastava, S. Bhardwaj and S. Saraswat, "SCRUM model for agile methodology," 2017 International Conference on Computing, Communication and Automation (ICCCA), 2017, pp. 864-869, doi: 10.1109/CCAA.2017.8229928. https://ieeexplore-ieee-org.proxy.findit.cvt.dk/document/8229928
- ↑ Z. Bougroun, A. Zeaaraoui and T. Bouchentouf, "The projection of the specific practices of the third level of CMMI model in agile methods: Scrum, XP and Kanban," 2014 Third IEEE International Colloquium in Information Science and Technology (CIST), 2014, pp. 174-179, doi: 10.1109/CIST.2014.7016614. https://ieeexplore-ieee-org.proxy.findit.cvt.dk/document/7016614
- ↑ Agile Software Construction, John Hunt ,Springer-Verlag London Limited 2006 https://link-springer-com.proxy.findit.cvt.dk/content/pdf/10.1007%2F1-84628-262-4.pdf
- ↑ Agile vs Waterfall SDLCs: What’s The Difference?, Muhammad Raza http://www.bmc.com/blogs/agile-vs-waterfall/