What is a Spiral Model in Software Development
03/12/2022

What is a Spiral Model in Software Development?

Table of contents:

    You’ve probably heard about the waterfall process model. Seems somewhat obsolete these days, right? 

    So, you’re likely more into the iterative process model. Well, what if someone combined these two? Sounds innovative, doesn’t it? 

    The truth is that this is nothing new since the first spiral model in software development emerged in… 1986. It was introduced by Barry Boehm. Granted that you want to know more about that model, buckle up and keep on reading – it’s all here.

    If you’re one of these people who have the ‘TL;DR’ thing, here’s a brief info of what you can expect from this article. You’re welcome!

    You’ll learn:

    • what’s the spiral model,
    • what it shows exactly in each of the quadrants,
    • how the spiral model usefully combines other models, 
    • what are its pros and cons,
    • and finally, when it’s best to use it in practice.

    What’s the spiral model?

    In software development, the risk is definitely something that should be avoided or at least reduced. The spiral model comes in handy in this matter. Do you know what SDLC (Software Development Life Cycle) is? If not – check our article about SDLC models. However, you should already have that knowledge, since you’re here reading about the spiral model. As mentioned above, the spiral model is helpful in risk handling, especially in large projects.

    Steps of spiral model in development

    At first glance, it looks just like a coil. Probably that’s why it’s called the spiral model. The point is that each loop of this spiral represents a specific phase in the software development process. 

    How many loops should be there? It depends on the project. It’s up to the project manager who takes care of determining the number of phases in a particular case. And that’s precisely what our expert project managers at CSHARK do.

    The spiral model – what does it show exactly?

    Firstly, you should pay attention to the radius of the spiral. It represents the costs at any point. So, briefly – it helps keep your budget in line. Cool, right? 

    Well, that’s not all. You can also keep track of the progress at a glance – the angular dimension shows exactly that aspect of every phase. Moreover, there are quadrants, and they also have a special meaning. Here’s the long story short:

    1st quadrant – it’s all about planning

    Every successful project starts with setting goals and analysis. This quadrant also contains the space for estimating the costs, identifying requirements, and figuring out possible alternative solutions. We know it works well, and that’s why custom software development services is our bread and butter. No budget burnout here, we value resources (such as time and money).

    2nd quadrant – rock-solid risk analysis

    Time for evaluation. As you know, time is money, so it’s best not to waste it on developing unsuccessful solutions. In this phase, our pros select the best possible option for further development. And then, they take care of identifying the risks and implementing a proper strategy to ensure security. It’s crucial, as the new game-changing digital product cannot be vulnerable to cyberattacks. Of course, there’s more to that than only cybersecurity. It’s about finding any flaws in the product and resolving the issues.

    3rd quadrant – the engineering magic

    In this phase, the experts take care of what they do best – building software. It’s all about crafting the architecture, creating miracles in terms of remarkable product design, building the prototype, testing, and finally deploying the result. Basically, this phase ends with a physical result that comes from the two previous phases. However, there is one more quadrant to go – the newly created software needs to be evaluated.

    4th quadrant – the review stage

    If it’s the end point of the spiral – the new product is ready. But as there are many loops along the way, it’s the phase of evaluation. The team is focused on finding out what worked and what didn’t. Depending on the project, the software can also be evaluated by the customers. Anyway, it’s time to review the result of the effort and move on to the first quadrant – plan the next steps and repeat the cycle.

    The spiral model – a useful combo of models

    It’s true that the spiral model combines the waterfall model and the iterative model. But it has much more to offer – it incorporates the prototype approach, as well as has the valuable aspects of the evolutionary model. Risk is kept at bay, as this model enables the option of providing the scope to create a prototype at every phase of the development. Moreover, continuous analyses in every loop help identify the issues along the way. Now that is flexibility! Sounds impressive? Keep on reading, we’re going to tell you more about the pros and cons (yes, there are such) of the spiral model. Ready? Let’s go.

    The spiral model – what are the pros?

    You already know that this model is useful and has many advantages. Surely, it helps developers work smart and productively at the same time – the large projects can be chopped into smaller parts, which are much easier to handle. What are the other benefits of using the spiral model? 

    • Flexibility – the requirements may change (and they usually do), but they can be implemented fast during the process of development. Keep that in mind, as the only constant thing in the world is change (we think of users’ needs and expectations in this case).
    • Risk handling – there are analyses conducted in each phase, thus, facilitating risk management is straightforward in this model.
    • Large projects handling – no need to explain, breaking the massive project into smaller parts just makes the life of the software development team easier.
    • Customer satisfaction – digital products are made for people, so the satisfaction of the target audience is a crucial factor. In this model, the users can evaluate each prototype, which is priceless.
    • Resource saving – this is related to all the previous points. Briefly – time and money are not wasted, and everyone is happy – it’s as simple as that.

    The spiral model – what are the cons?

    As with any other thing in the world, there are some limitations – this applies to the spiral model as well. Let’s see what are the disadvantages of this model.

    • Complexity – the team must adhere to the protocols, and the spiral model is much more sophisticated in that matter than the other models. Furthermore, it means more documentation throughout the whole process.
    • Dependence on risk analysis – honestly, it’s about one thing – the experts in risk assessment involved in the project. Without proper expertise in this field, the project will most probably fail.
    • Time management – remember that the number of loops may vary. It takes a real master in project management to make things not fall behind schedule.
    • The cost – let’s be honest here, the spiral model is expensive. It’s not an issue for large projects, but it’s simply not sustainable for smaller ones.

    The spiral model – when to use it?

    There is one more thing worth mentioning – when the spiral model is the best option and why? Think of it as a summary. Worry not, we will keep it short. Here’s the list:

    • if it’s a large project,
    • if the project requires frequent releases,
    • if there’s a need for crafting a prototype,
    • if the risk handling is crucial for the project (medium- and high-risk levels),
    • if the requirements are complex (or even unclear),
    • if the changes have to be applied frequently (due to various reasons).

    As you can see, the spiral model can be very useful, unless it’s a small project (and a small budget). 

    This model helps make things simple – which is something we value at CSHARK (see who we are and how we work). We’re not fans of being busy, we’re fans of being productive. 

    Do you have a vision that needs to be transformed into a game-changing product? Drop us a line here, since every successful project starts with a conversation.