What is iterative model advantages disadvantages and when to use it
What is iterative model advantages disadvantages and when to use it
Try QA
Main navigation
Study material for ISTQB Exam Certification Foundation level, Premium & Free for ISTQB and ASTQB Exam, Certification questions, answers, software testing tutorials and more
What is Iterative model- advantages, disadvantages and when to use it?
An iterative life cycle model does not attempt to start with a full specification of requirements. Instead, development begins by specifying and implementing just part of the software, which can then be reviewed in order to identify further requirements. This process is then repeated, producing a new version of the software for each cycle of the model.
In the diagram above when we work iteratively we create rough product or product piece in one iteration, then review it and improve it in next iteration and so on until it’s finished. As shown in the image above, in the first iteration the whole painting is sketched roughly, then in the second iteration colors are filled and in the third iteration finishing is done. Hence, in iterative model the whole product is developed step by step.
Diagram of Iterative model:
Advantages of Iterative model:
Disadvantages of Iterative model:
When to use iterative model:
Iterative Model
By 
Priya Pedamkar
What is the Iterative Model?
The iterative model is also called an incremental model in which a particular project or software is broken down into large numbers of iterations, where each iteration is a complete development loop resulting in a release of executable product or software. A subset of the final product under development, which grows from iteration to iteration to become the final product or software. Prototyping, Rational Unified Process (RUP), agile development, Rapid Application development are examples of the iterative model.
Iterative Model
The SDLC (Software Development Life Cycle) is notably huge and abundant in numerous testing and development actions, techniques, methodologies, tools, and others. It includes intensive outlining and the administration, computation and arrangement. It is just following every certain effort of the software engineers that application or software is favourably created. The Iterative model is also a component of the SDLC.
Web development, programming languages, Software testing & others
A specific execution of a software development life cycle that concentrates on primary, uncomplicated execution, which then increasingly profits higher complication and wider characteristics setting to the ultimate system, is concluded. In brief, development in the iterative model is a manner of shattering down the software development of a huge application into shorter sections.
The model of the iterative model life cycle did not begin with whole stipulations. Particularly in the model, the development starts by designating and executing the only component of the software when analysed to recognize later specifications. Furthermore, in the iterative model, the process of iterative begins with a simplistic execution of a little collection of the software requisite, which iteratively improves the developing variants until the whole system is executed and prepared to be redistributed. Every Iterative model release is developed in a particular and established period of time known as iteration.
Moreover, the iteration concentrates on a particular assemblage of specifications. Every cycle finishes with a system that is used, for instance, a specific iteration outcome in an implementable release. The iterative Model enables obtaining previous stages, in which the alterations are made respectively. The ultimate outcome of the product is restored at the finish of the SDLC, the life cycle of software development. Usually, development in the iterative model is utilized in connection with accumulative development, in which an extended cycle of the software development is divided into shorter sections that are created upon one another.
Henceforth, the iterative model is utilized in the subsequent outlines:
The procedure of the iterative model is cyclic, not similar to the conventional models that concentrate on meticulous in gradual stages of the development procedure. In this entire procedure, only the primary planning is finished, fewer stages are replicated repeatedly, with the complicated of every cycle, gradually enhancing and software iteration.
Examples oF Iterative Model Design
Below are the examples :
1. User Interfaces
A requirement of a film company needs a custom system for equipment tracking, costumes, and props. The business section included is unusual for rendering specifications for technology-based projects. To evade the usual circumstances where developers continuously work for a month and build something that customers will decline, an iterative outline strategy is utilized. In a week, the developers and users sit twice to discuss through the recent system. Consumers experience the products and create new specifications that are rigorous prioritization down to fewer workdays. In this manner, the system emerges to be beneficial and simple to utilize.
Software Development Methodologies
Amir Ghahrai
In this post we’ll go through the different software development methodologies along with their advantages and disadvantages and when to use each model.
Iterative Model
An iterative life cycle model does not attempt to start with a full specification of requirements. Instead, development begins by specifying and implementing just part of the software, which can then be reviewed in order to identify further requirements. This process is then repeated, producing a new version of the software for each cycle of the model.
Consider an iterative life cycle model which consists of repeating the following four phases in sequence:
A Requirements phase, in which the requirements for the software are gathered and analysed. Iteration should eventually result in a requirements phase that produces a complete and final specification of requirements.
A Design phase, in which a software solution to meet the requirements is designed. This may be a new design, or an extension of an earlier design.
An Implementation and Test phase, when the software is coded, integrated and tested.
A Review phase, in which the software is evaluated, the current requirements are reviewed, and changes and additions to requirements proposed.
For each cycle of the model, a decision has to be made as to whether the software produced by the cycle will be discarded, or kept as a starting point for the next cycle (sometimes referred to as incremental prototyping.
Eventually a point will be reached where the requirements are complete and the software can be delivered, or it becomes impossible to enhance the software as required, and a fresh start has to be made.
The iterative life cycle model can be likened to producing software by successive approximation. Drawing an analogy with mathematical methods that use successive approximation to arrive at a final solution, the benefit of such methods depends on how rapidly they converge on a solution.
The key to successful use of an iterative software development life cycle is rigorous validation of requirements, and verification (including testing) of each version of the software against those requirements within each cycle of the model.
Advantages of Iterative Model
Disadvantages of Iterative Model
Incremental Model
The incremental build model is a method of software development where the model is designed, implemented and tested incrementally (a little more is added each time) until the product is finished. It involves both development and maintenance. The product is defined as finished when it satisfies all of its requirements. This model combines the elements of the waterfall model with the iterative philosophy of prototyping.
The product is decomposed into a number of components, each of which are designed and built separately (termed as builds). Each component is delivered to the client when it is complete. This allows partial utilisation of product and avoids a long development time. It also creates a large initial capital outlay with the subsequent long wait avoided. This model of development also helps ease the traumatic effect of introducing completely new system all at once.
There are some problems with this model. One is that each new build must be integrated with previous builds and any existing systems. The task of decomposing product into builds not trivial either. If there are too few few builds and each build degenerates this turns into Build-And-Fix model. However if there are too many builds then there is little added utility from each build.
Advantages of Incremental Model
Disadvantages of Incremental Model
When to use Incremental Model
Agile Model
The agile model is a combination of both iterative and incremental model by breaking a product into components where on each cycle or iteration, a working model of a component is delivered.
The model produces ongoing releases (iterative), each time adding small changes to the previous release (iterative). During each iteration, as the product is being built, it is also tested to ensure that at the end of the iteration the product is shippable.
The Agile model emphasizes collaboration, as the customers, developers and testers work together throughout the project.
An advantage of the Agile model is that it quickly delivers a working product and is considered a very realistic development approach.
One disadvantage of this model is that because it depends heavily on customer interaction, the project can head the wrong way if the customer is not clear about the requirements or the direction he or she wants to go.
V Model
The V Model is an enhanced version of the classic waterfall model whereby each level of the development life-cycle is verified before moving on to the next level. With this model, software testing explicitly starts at the very beginning, i.e. as soon as the requirements are written.
Here, by testing we mean verification by means of reviews and inspections, i.e. static testing. This helps in identifying errors very early in the life-cycle and minimizes potential future defects appearing in the code later in the life-cycle.
Each level of the development life-cycle has a corresponding test plan. i.e. as each phase is being worked on, a test plan is developed to prepare for the testing of the products of that phase. By developing the test plans, we can also define the expected results for testing of the products for that level as well as defining the entry and exit criteria for each level.
Like Waterfall, each stage begins only after the previous one has ended. This model is useful when there are no unknown requirements, as it’s still difficult to go back and make changes.
When to use the V model
Waterfall Model
The waterfall model is the oldest and most straightforward of the structured SDLC methodologies. There are strict phases and each phase needs to be completed first before going to the next phase. There is no going back.
Each phase relies on information from the previous stage and has its own project plan.
Waterfall is easy to understand and simple to manage. However, it is usually prone to delays as each phase needs to be reviewed and fully signed off before the next phase can begin.
Also, since there is little room for revisions once a stage is completed, problems can’t be fixed until you get to the maintenance stage.
This model works best when all requirements are known and flexibility is not required and the project has a fixed timeline.
What is Iterative Development – An Easy Guide for Beginners
The field of mobile and web development is constantly and rapidly evolving; better technologies are becoming available to developers and new development methodologies are being used to build software more efficiently. It is essential to be up-to-date with efficient software development methodologies. This article is about one of the Software Development Life Cycle (SDLC) methodologies called iterative development.
Let us begin with understanding what iterative development is. An iterative development model works on a systematic repetition of small cycles of software development known as iterations. It aims to achieve an optimal product towards the end. The process begins with specifying and implementing a part of the software. Then it is repeated to produce a new version of the software for each iteration until the finished product is achieved. That is why the iterative model does not attempt to start with a full specification of requirements.
At this point, you must be thinking about how the iterative software development model is different from the rest of the SDLC methodologies. Don’t worry! We will begin with a brief history of the iterative model. Then, we will move onto the iterative approach to software development, where we will explore some of the best practices involved in the iterative process model. Finally, we will end this article by looking at the pros and cons of the iterative methodology.
The History of Iterative Development Model
Before we delve into the iterative development process, let’s have a look at the history.
Back in the 1950s, the introduction of the Kanban method opened possibilities for the iterative SDLC model. The method was based on lean production which focuses on efficiency, swift delivery and iterative improvements. It could easily be upgraded to iterative methodology as well as applied to other SDLC methodologies.
Later, the iterative process model was studied in 1995. It was believed that the process of human learning is an iterative, trial and error one. Therefore, the same approach was considered to be applied in software development phases to develop better software, faster, and with fewer imperfections.
In 2004, Microsoft adopted an iterative strategy in software development, followed by other developers. In more recent years, with the introduction of Agile and Lean methodology in software development the focus has shifted to the approaches based on the iterative model to reduce life cycles and ensure an efficient product development process.
The Process For Iterative Development
The iterative development process is cyclical; unlike the waterfall model, it does not follow a rigid process. Once you are done with your initial planning, which does not necessarily have to be very well-defined, the rest of the steps for each iteration are carried out again and again with extensive testing in between until you reach the overall deployment stage.
Each iterative cycle is tested at its initial stage for software and system integration. The decision is made on every step to determine whether the produced outcome will be kept or discarded for the next cycle. This is also referred to as incremental prototyping because the software is developed by working on smaller chunks during each iteration.
Iterative Development Model
In other words, this SDLC iterative model allows the developers to access previous cycles which can be reviewed and changed, if necessary until all the requirements are met and the final product is delivered.
Following is the iterative development methodology for each cycle. To make it further easier for you, we will understand the steps with the help of an example:
Step 1: Planning and Analysis
The first step of the iterative life cycle is the planning, where the developers and clients sit together to identify software requirements, business and stakeholders’ requirements. At this stage, it is not necessary to identify risks associated with the project or worry about quality assurance requirements because this step will be repeated again for your next iteration which will make sure that the risks are overcome and quality is ensured.
Once all the requirements are identified, analysis is done to streamline the development process such as identifying database models.
For your ease, let’s understand through an example.
Iterative Steps – Planning and Analysis
Suppose, you want to develop a gaming application and that too in the least possible time. You have to incorporate three requirements for now: the menu page, the game and the scoreboard. Once you are done with your initial planning for each requirement where you will identify overall project requirements, your target audience, the content of the game, client’s requirements, etc. you will start with your first iteration which will focus on the basic template of the menu page, game and scoreboard.
Only when you are done with this step, you will proceed to the next one. This is how the iterative methodology works.
Step 2: Design
In iterative development, the design does not play an important role, compared to other steps. However, in this step, the design team can establish technical requirements such as language, services, and data layers and so on, for the architecture of the software.
Iterative Steps – Design
In the case of our gaming application example, at this step of iterative software development, the design team defines business rules, database along with data layers, languages, etc. you will require to develop a basic version of the three features. When you are done with this step, you will proceed to the next one i.e. implementation.
Step 3: Implementation
Now when you are done with the previous three steps, your next step is to start writing the code for your first version of the software. You will follow the coding guidelines and use various back end and front end technologies such as compilers, interpreters, debuggers, etc. to write the code.
At this step, you will build the technical architecture as well as the database and programs of your first iteration module.
Now, keep in mind, sometimes implementation and testing (which I am going to discuss next) are repeated side-by-side to ensure there are no errors left. Hence, if you doubt that you have written some part of the code incorrectly, after testing, you can rewrite your code and proceed to your next iteration.
Iterative Steps – Implementation
As in the case of our game app example, developers will start writing the code where they will make sure that every guideline from planning to design step is incorporated well. At this point, after developer level testing, if you feel the code is wrong or the software needs an upgrade, you go back to the planning step and start your second iteration.
Step 4: Testing
Once your code is written for your initial iteration module, it is time to test it for potential bugs or issues that might have been overlooked during the implementation step. You will perform unit testing that is testing individual units of codes; integration testing that is verifying units of code functioning properly when integrated; and will run a user acceptance test that is determining whether the systems satisfies the user requirements for that iteration.
Additionally, you will test your iteration module for potential hacks using different methodologies, which are not only limited to black box (having no access to source code), grey box (having partial access to source code) and white box (having full access to source code) methods.
Iterative Steps – Testing
In the case of our gaming application, once you reach testing, you will test using multiple testing methodologies. One of the most important testing methods is playtesting; you will provide your application to different audiences who will try to test it in different ways. In this case, they will choose the number of players from the menu page and play the game from different devices. If they find any problems, you will have to go back to the planning step and start working on your second iteration.
Step 5: Evaluation
Once all your steps are followed for each iteration, you will finally evaluate the entire project. You will hand over the project to the client, who will review the final product for its efficiency and validity.
So, according to our example, after testing, your audience or even you as a developer might have faced some issues in terms of functionality, user interface (UI) design, user experience (UI) design, etc. Therefore, at this stage, you will gather feedback and will start your next iteration from the very first step that is the planning.
Now, this is the first iteration cycle where you have successfully developed the basic version of your gaming application. To incorporate further changes in the final product, for example, to add new game levels, along with the client feedback, you will take your go back to Step 1, that is, planning, and follow every step again for your next iteration cycle, which will be an improved version of your software. The process will repeat until there are no improvements to be made.
Iterative Steps – Deployment
After you have successfully completed all the iterations, in our case your gaming application, the project is ready to be released. You will provide user documentation to the client where you will specify the guidelines to use the software.
If the client wishes to use the maintenance facility, you will also provide weekly or monthly maintenance to them.
When to Use Iterative Model
Now that we know the science behind the iterative process model, the important question which comes up is when to use it? You will use it when:
Furthermore, to choose the best method for your software, we have listed the pros and cons of the model.
Pros for Iterative Development
Cons for Iterative Development
Conclusion
To sum up what iterative development is, it is simply a software development life cycle model which works through small iterations to ensure efficiency and high-quality software at the end. This model can be a great choice for large software that needs to incorporate d feedback and review progressively during development rather than towards the very end. If you follow each step of this model properly, you will end up with a great product that is more likely to be in line with the desired functionality at the end, unlike software developed using the more rigid waterfall model.
We hope we were able to answer all your questions regarding the iterative process. If you still have any query, feel free to reach out to us and we will be happy to assist you. And If you are wondering what SDLC methodologies does GoodCore use while developing amazing custom software for clients, reach out to us and we shall let you know!
Rate this article!
Average rating 5 / 5. Vote count: 9
No votes so far! Be the first to rate this post.
Iterative Model – Software Engineering
Introduction
The iterative process model is a software development life cycle (SDLC) approach in which the initial development work is conducted based on initial requirements that are clearly defined, and subsequent features are added to this base software product through iterations until the final system is completed. This SDLC approach does not aim to create a comprehensive specification plan. Instead, the iterative development model is a method for breaking down any major software development project into smaller chunks. It is specifically designed to start with the bare minimum requirements and only construct a portion of the program iteratively. Post that, the prototype is examined again for any extra requirements and then the rest of the planning, requirement analysis, deployment, and maintenance are all conducted. This helps in identifying risks associated with the requirements at a early stage and mitigate them.
Features of the Iterative Model
Following are some features of the iterative model:
Phases of the Iterative Model
1. Requirement and Planning Stage:
During this phase, the business requirements are collected, and an analyst determines whether or not they will be met within the allocated budget. It is used to layout the business needs in detail and the System information (hardware or software) is gathered and evaluated for feasibility.
2. Design Stage:
In this phase, the project team gets the complete set of requirements to begin their work in a particular direction. They use different figures like a data flow diagram, class diagram, activity diagram, state transition diagram, etc to get a clear understanding of the software design and help them proceed with the development. Developers come up with many potential solutions based on their analysis. Additionally, the size and criticality of the project is also an important factor in determining the level and complexity of design for the project.
3. Coding Stage:
The actual construction of the system begins at this point in the project. This stage will be guided by the analysis and design resulted from the Design Stage. All of the requirements, planning, and design plans are executed and coded. The developer will implement the chosen design using predetermined coding and metrics standards. During the code development, they must implement a unit test at each level. This stage should aim to achieve the goal of developing fully functional, testable system for that iteration. Depending on the project, the complexity of efforts and time spent on this iteration will vary.
4. Testing Stage:
This step involves testing the current build iteration to a set of standards and norms to see if it meets them. Performance testing, stress testing, security testing, requirements testing, usability testing, multi-site testing, disaster recovery testing, and so on are all examples of this type of testing. A developer or a tester has to ensure that fixing one bug does not lead to emergence of additional bugs in the system. The tester can write new test cases or reuse ones from earlier builds, but testing is a top priority because any errors would affect the software’s specification thereby impacting the business. We can also check in with the project stakeholders to run some tests and inquire about any feedback they may have.
5. Evaluation Stage:
This is the last stage of the iterative model. After all the processes are complete, the system constructed up to this point is thoroughly evaluated. The system is examined by the development team, stakeholders, and other teams responsible for developing the project to see if the outcomes satisfy their expectations. A new requirement plan is produced and implemented as part of the next iteration cycle based on this.
Iterative Model Applications
Below are some of the scenarios where the iterative model is used actively:
The use of an iterative model does not limit to one industry. Due to its features like parallel development, multiple testing, early risk identification, etc. It is adapted by various industries like Electronics, marketing, sales, etc, as discussed above.
Advantages
Before using the Iterative model in the Software Development Life Cycle(SDLC), it is critical to understand its benefits. The most significant benefit of this model is that it is adopted early in the software development process, allowing developers and testers to identify functional or design faults as early as possible, allowing them to take corrective action on a restricted budget and mitigate risks. Other advantages or benefits of this model include:
Disadvantages
Although the iterative paradigm is extremely beneficial, it does have some flaws and limitations. Furthermore, since every requirement is not collected at the start of the entire project’s life cycle, questions about system structure or outline may arise at later stages. Following are some of the disadvantages associated with the iterative model:
Conclusion
This brings you to the end of the blog. Now, you have got the brief understanding of the iterative model. The final product, which was created iteratively, meets the user’s requirements. This model allows you to spot any major design or planning issues in the process model and fix them as early as possible as this model iscyclic in nature. Furthermore, the iterative approach is quite useful since it can accept modifications in the system’s original requirements. This approach can also be used in conjunction with other models such as the incremental model, Agile methodology, and so on.
Coming up to the final thoughts, the selection of model depends upon the type of project you are working on. With each project, one model can overpower the other one based on several factors.
Q: Where is iterative model used?
A: Some of the scenarios where iterative model is used is as follows:
Q: Is waterfall model iterative?
A: Iterative model is similar to the waterfall concept, the only difference is that iterative waterfall allows you to go back to a previous phase and update the criteria, as well as make some changes if needed.
Q: What are the limitations of the iterative model?
Below mentioned are the important limitations of iterative model: