8 questions that define

When people talk about U.S. Food and Drug Administration (FDA) design controls, they often place a lot of emphasis on design inputs and outputs, verification, transfer, and the design history file.

All good things, of course; without them, you won’t meet FDA requirements for your design controls.

The problem, however, is that too often people forget to ask themselves “Why?”

Let me put it another way: Why are you creating this device in the first place? I’m assuming you want to meet a medical need of some kind. If that’s true, don’t start with what it does. Start with who it’s for.

The user’s needs are often given lip service in the medical device world, but there isn’t much emphasis on finding what those needs are.

According to the FDA, all design controls should start with user needs and cascade down into the other stages of the process.


There are two things to think about when defining user needs. First, “intended use” is the general purpose—what the device does. Second, the “indications for use” describe the medical conditions your device will help diagnose, treat, prevent, cure, or mitigate.

On the surface, defining user needs for medical devices probably seems simple. After all, you observed a need, which is what gave you the idea in the first place. Even if it seems plain to you, documenting the user’s needs at the outset will help to ensure the whole team sees the same vision, and that you’re all working toward the same goal. When you get to the design verification, it’s much easier to know if you’ve met your goals if the goals have been well-documented.

As you think through the user’s needs, here are some of the most important questions to ask yourself: 

1. What do you want the device to do? Does it cure a disease completely or help with the symptoms?

2. Who is going to use it? Are the users young or old? Do they have other medical conditions in addition to the one you’re treating for? These questions will make slight differences to the design and function of any device.

3. When will it be used? Occasionally or all the time?

4. What important attributes or features should be considered? This is the nitty-gritty, really making sure you think through all the ways this device could help people.

5. How will the user interact with the device? Will the user be able to work it on her own, or will she need professional help with it?

6. What type of procedures will the device be used for? Is it for surgeries, rehab, or daily life, and for what types of activities in these categories?

7. Is the device used once, or repeatedly? This will make a difference in manufacturing and quality requirements.

8. What other products will the device interact with? You’ll need to think through how to make your device compatible with all other medical equipment with which it will be used.

There are many more questions, all depending on the type of device you’re creating. Ask yourself and the team these questions, and write the answers down. They will jumpstart the process of creating your design inputs and put you firmly on the path to creating your device. Don’t worry too much about official language or understanding every single thing about the user.

Get started, and you can always adjust—as a team—as you go.

User needs are just the beginning of the design controls process.

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