As software continues to develop at an overwhelming speed, it’s important to back it up, and look at how it’s made. Two of the most popular development methods are waterfall and RAD (Rapid Application Development). Here’s a good comparison of the two, along with some extra notes about how Agile development principles compare.
What Is the Waterfall Model?
The waterfall model of development was established many decades ago as a definitive way to approach engineering projects. Its name comes from the fact that progress flows down sequential steps.
The engineering team will first meet with the client to discern all of the requirements. Then the engineers design a solution to meet the requirements. Next, they build the solution. Once it is ready, they take the solution back to the client for testing, and after fixing all the bugs, they deploy it and carry out scheduled maintenance.
Pros and Cons of the Waterfall Model
- Objectives are easy to translate and align to
- Enforces discipline and enables strict adherence to timelines
- Planning takes absolute precedence enabling predictability
- Testing specifications are predetermined
- Issues are identified early
- Delivery times are typically longer
- Very rigid and may not allow for a change in direction
- Will require a hard restart if changes are significant
- Does not include the client or end user in the development process
What Is the RAD Model?
The rapid application development methodology came as a response to problems when applying the waterfall model to software development. Software is uniquely different from other types of engineering because changes can be made almost immediately and even very late in the development process.
Pros and Cons of RAD Model
- Significantly reduced development times
- Customization is easy owing to the segmentation of system components
- Easier to reach client consensus since they are actively involved in development
- Components are reusable
- Accommodates multiple changes in expectations, goals, and requirements
- Relies heavily on a skilled team of developers and testers
- May not be best suited for projects requiring high sophistication
- Requires clients and developers to be in active collaboration
- Can only be used to build modularized systems
RAD is based on four core concepts:
- Reusable code in an accessible repository
- Quick prototyping
- Constant client feedback
- Building usable software as quickly as possible
The client and developer work together to create an end product that functions exactly as the client wants.
Choosing Your App Development Stack: A 11-Point Checklist
Waterfall vs RAD: Which Is Better?
Although RAD is a unique model for software development, that doesn’t mean it’s always better. In fact, many developers still prefer the waterfall model. Here are several different factors that can help you choose which model is best for you.
|Time||Sticks to a planned schedule, needs to start back at the beginning if significant changes emerge||Open-ended, the project is done when the client is happy|
|Ideal Size of the Project||Very small and very large projects||Small and medium-sized projects|
|Developer Team Size||Can be small to large||Needs to be small|
|Developer Experience Level||Can be junior to senior if the specs are clear||Multi-talented, very experienced and flexible|
|Ideal Project Type||On-premise, desktop applications||Web-based, mobile apps|
|Ideal Client||Extremely hands-off, knows exactly what he/she wants from the beginning||Good communicator, open to suggestions, has the big picture, available|
|Worst client||Changes mind frequently, want to be involved all the time, scope creep||Inaccessible, indecisive, uninterested|
|Risk||Risk assessed at the beginning is accounted for, but not in the middle||Respond and prepare for risks continuously|
|Approach to change||Change is extremely negative||Change is welcome|
|Best time for changes||At the very beginning||Anytime|
|Project Management Style||Stick to the original plans and dates||Very adaptive, more like driving an elephant|
|Use of new technologies||No changes after specs are set||New changes can be brought in anytime|
|Feature Management||Every feature in the spec is built||Only features that prove to be useful are built|
|Updates and Versions||Planned and methodical||Ad-hoc and quick|
|Costs||Fixed costs, assuming no changes||Variable, depending on the number of iterations|
|Prototype||Delivered after the entire app is fully functional||Working model delivered as soon as possible|
What About RAD Vs Agile? Are They the Same Thing?
When you look at agile vs RAD, they are very similar concepts. Both are reactions to the standard waterfall method. The core element of RAD is to quickly design and deploy prototypes that are later updated and modified into production-grade code. RAD is also known as the agile model, where the software development lifecycle is divided into sprints.
The differences between RAD Model and Agile are still emerging, as they aren’t usually seen as conflicting. However, there are some key distinctions you can make.
Focused on building a working model of an app in the shortest time possible.
Focused on breaking down the development cycle into smaller ‘sprints’.
May demonstrate a working model to clients in the middle of development.
Waits till the product or feature is completely built before showcasing it to the client.
Build the easiest parts of the product first so as to showcase the working model as soon as possible.
Addresses the most difficult feature/part of the product first.
Prioritizes functionality over UI/UX.
Considers UI/UX while the product is being built.
Which One Is Right for You?
If you are considering waterfall vs RAD or even RAD vs Agile, the key questions you should ask have to do with the nature of the project and what kind of developers you have.
As clients, project leads, and developers become more skilled, there may be less of a need to follow the typical waterfall methodology. You can move to a more adaptive and faster means of development. But if your team is fairly inexperienced, relying on a traditional development model may be better in the beginning.
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