Waterfall Model Vs Agile

This article is a comparative analysis of waterfall model vs agile model of software development. Checking out this comparative analysis may help you in choosing which model is conducive for your own software development project.

Software development, like any other business process, has certain targeted goals which must be achieved in a fixed frame of time. There are various strategies for achieving these software development goals. Two of the most popular software development models are the ‘Waterfall Model’ and the ‘Agile Model’. This article makes a waterfall model vs agile model comparison, that will serve to point out the differences in the two different methods of software development.

Waterfall Model Vs Agile Model: History

Before we get into comparing waterfall model vs agile model, let us have a look at the developmental history of these two models.

Waterfall model in software engineering

got formally introduced as an idea, through a paper published by Winston Royce in 1970. However, ironically, he himself had introduced it as a flawed method of software development, vulnerable due to its many shortcomings. Every methodology has takers and waterfall model has been successfully implemented by many software companies. The waterfall model philosophy was inherited from the hardware manufacture strategies and construction strategies that were in practice during the 1970s. That is why it has a very structured approach to software development.

Waterfall model explained

later will clarify what I am trying to say here.

On the other hand, the agile model of software development evolved in the 1990s when developers decided to break away from traditional structured, segmented, bureaucratic approaches to software development and move towards more flexible development styles. The ‘Agile’ or ‘Light Weight’ methods as they were called, were formally defined in a research paper by Edmonds in 1974. Some of the most prominent and popular agile methods of software development, that subsequently evolved are ‘Scrum’ in 1995, ‘Crystal Clear’, ‘Extreme Programming’ in 1996, ‘Adaptive Software Development’, ‘Dynamic Systems Development Method’ in 1995 and ‘Feature Driven Development’. In 2001, a group of pioneers in agile software development came together and declared the ‘Agile Manifesto’, which is a set of canonical rules of sorts for, agile software development methods.

Waterfall Model Vs Agile Model: Conceptual Difference After the short interlude of history, let us start the actual waterfall model vs agile model comparison, by starting with the major conceptual differences in the two approaches. Then we will compare the difference in software development life cycle, involved in both approaches. Let us discuss the waterfall model advantages and disadvantages after delving into the main concept. Waterfall model of software development, as the name itself signifies, is a sequential process of software development. Like in a waterfall, the water progressively falls from one altitude to the lower, in a similar way, the production cycle progresses sequentially, from one stage to the other (illustrated by a waterfall model diagram

in textbooks). The waterfall model phases of software development are as follows: requirement specification, conception, analysis, design, coding, testing & debugging, installation and finally maintenance. In this sequentially structured approach, the development team goes ahead to the next stage of development only after the first is fully accomplished. Software development companies adopting this model spend considerable amount of time in each stage of development, till all doubts are cleared and all requirements are met. The belief that drives this kind of software development model is that considerable time spent in initial design effort corrects bugs in advance. Once the design stage is over, it is implemented exactly in the coding stage, with no changes later. Often the analysis, design and coding teams are separated and work on small parts in the whole developmental process. Emphasis is placed on documentation of every stage of software development.

Now let us have a look at the agile software development method. Compared to the ‘set-in-stone’ approach of waterfall development models, the agile models, as the title suggest, focuses on ‘agility’ and ‘adaptability’ in development. Instead of one time consuming and rigid development schedule, agile models involve multiple iterative development schedules that seek to improve the output with every iteration. Each iteration goes through the all the steps of design, coding and testing. The design is not set in stone and is kept open to last minute changes due to iterative implementation. The team structure is cross functional, closely knit and self-organizing. The design idea is never totally frozen or set in stone but is allowed to evolve as new ideas come in with each release. Less importance is given to documentation than speed of delivering a working program.

Waterfall Model Vs Agile Model: Efficiency

In the ongoing comparison of waterfall model vs agile model, let us see how these two ideologies compare with respect to development efficiency. Efficiency is decided by the quality of ultimate software product, the number of bugs and the development time consumed. Through my own research into the working of both these models, I found the agile models to be more efficient than the waterfall model, due to its adaptability to the real world. The ‘One Phase’ and ‘Rigid’ development cycle makes it difficult to make last minute changes in requirements or design. While the agile methods, due to their iterative and adaptable nature, can incorporate changes and release a product in lesser time. Of course, agile models are not perfect either, but they are certainly more widely applicable than the waterfall model.

Waterfall Model Vs Agile Model: Suitability

The water fall model is suited for development of programs that are already stable. That is, their design does not need a major makeover. In situations where the designers of a software can accurately predict the flaws that may arise can be developed through a waterfall model. Despite all its flaws, a waterfall model design is easier to manage and the development costs can be ascertained before hand.

Agile models are applicable in every area of software development. It depends a lot more on the team effort of above average programmers, than relying on a few expert programmers. It is best suited for web based applications where its iterative nature helps in incorporating and correcting the various bugs that arise over time.

So, this was a waterfall model vs agile model comparison, that tried to compare the basic differences between the two. What is ideally needed is a model which combines the accountability and predictability of a waterfall model with the agility and adaptability of the agile model. That is, an effective balance between the two ideologies can create a more efficient software development model.