Are you again debating Agile with Standard Waterfall Methodology? || Agile Vs. Waterfall Methodology

At a very broad level we can say that classic waterfall method stands for predictability, while Agile methodology spells adaptability.
 

Here we shall mainly look at Advantages and Disadvantages of Agile Methodology. Finally we shall do a comparison of Agile and Waterfall in different contexts. 

Advantages of Agile Methodology - 

1. Focus on the rapid delivery of business value.

2. Agile development accelerates the delivery of initial business value, and through a process of continuous planning and feedback, is able to ensure that value is continuing to be maximized throughout the development process.

3. Easily adapting to changing requirements throughout the process.

4. Much more accurate visibility into the actual progress of projects is available.
 

5. Face to face communication and continuous inputs from customer representative leaves no space for guesswork.

Refer http://www.versionone.com/Agile101/Agile_Benefits.asp for more detailed information around the same.

Disadvantages of Agile Methodologies -

1. In case of some software deliverable, especially the large ones, it is difficult to assess the effort required at the beginning of the software development life cycle.

2. There is lack of emphasis on necessary designing and documentation.

3. The project can easily get taken off track if the customer representative is not clear what final outcome that they want.

4. Only senior programmers are capable of taking the kind of decisions required during the development process. Hence it has no place for newbie programmers, unless combined with experienced resources.

HERE IS HOW WE CAN COMPARE WATERFALL MODEL WITH AGILE METHODOLOGY -

- Once a stage is completed in the Waterfall method, there is no going back, since most software designed and implemented under the waterfall method is hard to change according to time and user needs.  The problem can only be fixed by going back and designing an entirely new system, a very costly and inefficient method. Whereas, Agile methods adapt to change, as at the end of each stage, the logical program, designed to cope and adapt to new ideas from the outset, allows changes to be made easily.  With Agile, changes can be made if necessary without getting the entire program rewritten.  This approach not only reduces overheads, it also helps in the upgrading of programmes.

- Another Agile method advantage is one has a launchable product at the end of each tested stage.  This ensures bugs are caught and eliminated in the development cycle, and the product is double tested again after the first bug elimination.  This is not possible for the Waterfall method, since the product is tested only at the very end, which means any bugs found results in the entire program having to be re-written.

- Agile’s modular nature means employing better suited object-oriented designs and programs, which means one always has a working model for timely release even when it does not always entirely match customer specifications.  Whereas, there is only one main release in the waterfall method and any problems or delays mean highly dissatisfied customers.

- Agile methods allow for specification changes as per end-user’s requirements, spelling customer satisfaction.  As already mentioned, this is not possible when the waterfall method is employed, since any changes to be made means the project has to be started all over again.

- However, both methods do allow for a sort of departmentalization e.g. in waterfall departmentalization is done at each stage.  As for Agile, each coding module can be delegated to separate groups.  This allows for several parts of the project to be done at the same time, though departmentalization is more effectively used in Agile methodologies.