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Risk Modelling in Software Development: A Look at Three Key Approaches

Risk modelling is an indispensable component of software development, designed to identify, assess, and manage potential hindrances that could disrupt a project’s progress. There are numerous methodologies used for risk modelling, each with its unique strengths and limitations. In this article, we will explore three widely-used approaches: Risk Matrix, Fault Tree Analysis (FTA), and Service Blueprint.

1. Risk Matrix

The Risk Matrix, or Risk Assessment Matrix, is a popular method in risk modelling. It enables teams to visualise and prioritise risks based on their probability and impact.

On a Risk Matrix, the x-axis typically represents the likelihood of risk occurrence, while the y-axis indicates the impact severity. Each identified risk is plotted on this matrix, offering a clear visual representation of which risks require immediate attention.

Despite its simplicity and ease of use, the Risk Matrix may oversimplify complex risks due to its binary nature and does not consider the interdependencies of risks.

2. Fault Tree Analysis (FTA)

Fault Tree Analysis is a top-down approach that employs Boolean logic to analyse the sequence of events leading to a failure (or fault). Each ‘tree’ starts with a single event – the failure under investigation – and branches out into all possible conditions and faults that could result in that event.

FTA is especially useful in quantifying risk probabilities and illustrating how different factors contribute to a failure. However, it requires an in-depth knowledge of the system and can become unwieldy when dealing with complex systems.

3. Service Blueprint

Service Blueprint is a user-centered approach to risk modelling, where a visual diagram is used to understand the relationships between different service components – people, props (physical or digital evidence), and processes – that are directly tied to touchpoints in a specific customer journey.

Service Blueprints enable teams to identify areas where a user might experience difficulty, thus highlighting potential risks. This approach is extremely useful when developing software that is highly user-focused.

However, creating a service blueprint can be a time-consuming process, and it requires a deep understanding of the user journey, which might not always be completely understood in the early stages of software development.

Read more about what a service blueprint is here.

“Risk modelling is a critical part of software development, aiding teams in anticipating and managing potential issues. The choice of approach largely depends on your project’s specific needs and resources.”


Risk modelling is a critical part of software development, aiding teams in anticipating and managing potential issues. The Risk Matrix, Fault Tree Analysis, and Service Blueprint each offer unique benefits and challenges, with the choice between them largely depending on your project’s specific needs and resources.

What risk modelling approach do you use in your software projects, and why? We invite you to share your experiences and insights in the comments below.