Waterfall vs Agile in software development: simple explanation of differences
Probably almost every organization working in the service sector, regardless of their field of activity, faced a problem where, due to initially incorrectly set tasks or sudden customer corrections that occurred during the project, it was necessary to completely redo it. Because of this, the deadlines were broken, the customer could in most cases remain dissatisfied with the results of the work (not to mention exhausted executors) and, as a result, refuse further cooperation with the organization. Such situations repeatedly accompanied the cascade development method (Waterfall) preceding Agile, in which next stage of the process began only after the completion of the previous one. If you transfer this example to the IT sphere, then the executing company had nothing to show the customer at intermediate stages of development. Moreover, many labor resources remained unused for a long time (for example, at the time when the architects were working out the algorithmic structure of the software, testers, programmers, designers and other employees of the company were idle). Of course, such a development scheme in many cases bring many faults. Thus, it was replaced by Agile. What are its unique traits?
Agile procedures in software development are a set of approaches that involve the iterative workflow, the dynamic formation of requirements and their implementation, ensured by constantly interacting self-organizing working groups consisting of varying specialists.
Therefore, we can distinguish a number of fundamental differences between Waterfall and Agile:
– Waterfall is a strictly sequential process in which a new stage of software creation cannot be started earlier than the previous one is completed. In turn, Agile is a flexible methodology that allows team members to be constantly involved in the development process;
– Projects created using the Waterfall methodology have predetermined requirements, while in Agile-projects requirements can constantly change;
– When developing using the Waterfall methodology, if you make changes, you will need to start the development process from the very beginning. In turn, the Agile methodology workflow would require only minor corrections.
To summarize the above, let us present the Agile methodology in software development manifesto, consisting of 4 major interrelated theses: Theses of Agile in software development
- People and interaction between them are more important than working processes and tools for their implementation;
- Correctly working software product is more important than the previously approved documentation;
- Fruitful cooperation with customer is more important than the contractual obligations;
- Changes in the originally established plan are inevitable, so the process participators must accept them and adapt.
Methods of Agile in software development
Surely at this stage of reading, you already wondered how Agile methodology works? There are several practical implementations of the Agile methodology. These include such methods as Scrum, Kanban, Extreme Programming, Lean Software Development, Crystal Clear and many others. Below we will consider in more detail the first two of them since they are most often practiced by companies that build their labor processes according to the Agile model.
Scrum is one of the Agile models, describing the development process as a set of strictly ordered micro-tasks, each of which must be implemented in one iteration (sprint), which lasts for 1-2 weeks. After each sprint, the customer if they so desire can test the working product with new features to correct their further wishes and requirements. During the sprints, the team uses various artifacts (lists of requirements to the functionality of the finished product ordered by importance), as well as burndown charts – special diagrams showing the amount of work done and remaining. In addition, at the end of each sprint, all team members gather to discuss what has been done and what is to be done during the next sprint. As a rule, such sessions take no more than half an hour and are not of a purely formal nature as is the case in standard companies. They remind more of a team of comrades meetings whose activities are aimed at solving the same problem. All this is done to reduce the distance in communication between experienced workers and beginners, and connect the former to solving the problems of the latter.
We must also note that inherent to Scrum is the assigning of emphasized roles with specific responsibilities that do not change during the working process to all the project development participants:
– Product Owner, who is an expert in the product, requirements, and priorities of the customer;
– Scrum Master – the person responsible for supporting the team, clarifying the organizational structure and processes of Agile;
– Scrum Participants – employees, participating in the development process, such as architects, programmers, testers, designers, etc.
The Kanban model is a less rigorous approach to software development than Scrum, implying visualization of future tasks. Typically, having broken the process of creating a project into subtasks, the manager uses either a regular physical or software board placing on it sticky notes or, respectively, virtual stickers, each of which is assigned to a separate task and is dyed in a color that determines its priority. The use of this model makes sense when some employees regularly fail to do the incoming assignments on time. In this case, nobody sits idle, and if the currently free employee sees a task on the board falling behind, they join the team assigned to it. This approach allows not only increasing the efficiency of the current workflow but also influencing positively the productivity of the team in whole, thanks to the opportunity to exchange valuable experience between employees within the company. Thus, unlike Scrum, in Kanban, there are no strictly assigned roles and time-limited sprints, and tasks can be more extensive and cover the greater functionality of the future software.
Advantages of Agile in software development
Agile companies receive these benefits:
– Admissibility of work in the absence of a clear vision of the result;
– Possibility of rapid adoption of changes to the project with a minimum number of amendments to its finished part;
– Accelerated error elimination due to constant testing of the work in progress;
– Possibility of continuous improvement of the project in the development process;
– Improvement of collective interaction;
– Improvement of cooperation with the client.
Disadvantages of Agile in software development
Despite the apparent perfection, Agile in software development is not without some drawbacks, among which are the following:
– Lack of an established release date for the finished product due to constantly changing requirements;
– Need to maintain good collective interaction;
– Reduction in the documentation importance;
– The dissonance between the results planned at the beginning of the project and the released product.
Implementing the Agile in software development methodology
In order to start working with Agile, you need to learn how to split the general list of tasks directly related to the project implementation into smaller ones that can be solved in single iteration (several days long, as is typical for the Scrum methodology or implying an arbitrary and longer period, which is typical for Kanban).To date, different Agile workflow organization methods (Scrum, Kanban and different hybrid approaches based on those two being the most popular) are successfully practiced by the vast majority of IT companies, and the question: "What is Agile?" is one of the most frequently asked at IT job interviews. Thus, taking into account all the advantages and disadvantages of Agile in software development, we can come to the conclusion that this is, nevertheless, an incredibly effective methodology for organizing the development process, which provides the most fruitful cooperation for both parties - the customer and the executant.