Person using interface analysis to develop project requirements

Project Requirement Gathering: Interface Analysis

A key element of gathering project requirements is interface analysis. Put simply, this is the process of understanding how people, software, and hardware interact with each other and how your project will need to handle these elements.

It’s a research-centric process that will mean you understand how all parts of your project trigger reactions in the system and affect their environment. Once you know how everything works with each other, you’ll know what you need to do in your project to make it work seamlessly.

In this article we’re going to explore:

  • Why interface analysis is useful
  • How to go about the process
  • The positive outcomes you’ll achieve
  • The concerns you should be aware of

So you that you can better understand how it’ll fit into your requirement gathering process for your project.

What is interface analysis used for?

Your project is likely to have many elements. Every part of the final product or service needs to interact smoothly with all of the other parts. This is where you get interfaces: where different parts of your project feed into each other.

Interface analysis is particularly useful to complete for projects that’ll be:

  • Multi-level
  • Cross departmental
  • Comprising many components

Because these types of projects have many dimensions and interactions to understand.

You will be able to identify boundaries, understand functionality, and know all the inputs and outputs. With this information, you’ll know what will be required from your project.

Completing interface analysis

As a process, it’s research and analysis heavy. There’s likely going to be minimal contact with stakeholders when doing interface analysis.

It’s useful to do this research before you do other activities such as focus groups or interviews. These are where you can explore issues you’ve found and seek opinions on how the interfaces work in practice.

To complete interface analysis you need to complete these steps:

  1. Make a thorough review of existing systems. This will allow you see where all of the different interfaces are.
  2. Build a context diagram to understand who or what is the sender and the receiver of the data in the system.
  3. Use this diagram to break it down into a data flow diagram. You’ll be better able to visualise the interfaces with this information at hand.
  4. Document all the events that trigger a reaction within the system so you can see all the places interactions take place
  5. Note all possible inputs and outputs so you have a complete understanding of how each piece affects the others

Reasons to complete interface analysis

Understanding the interoperability of a system will tell about lots of things you need to consider. Knowing how two pieces of the project need to work together will ensure you are able to build in these requirements early.

When you know there are going to be challenges to get a piece of software to pull data from an external system, or have a human be able to make a machine work safely, you can plan this into your project. Testing can be allowed for, meaning there won’t be unnecessary delays.

Other benefits include knowing the current pinch points so you can work through or around them and being able to plan inter-area collaboration.

Issues to be aware of with interface analysis

This is process that you’re going to tackle early on in your requirement gathering. It only gives you an external overview and analysis.

You don’t get any opinion in this research. The hard facts of how things work together are useful, but it is only part of what you’re looking for to successfully manage a project.


Using interface analysis within your project requirement gathering process should come towards the beginning of the process. It’s an important tool to see how all of the elements of the current system work. You also need to know about new interfaces.

Once you know everything that is going to go into and come out of the system you can understand how it feeds into your project. This hard data can then be built upon when discussing lived experiences with your stakeholders.