Dev Guide

Why Stage Matters

Think of development as a story you’re telling. In the early chapters, you don’t need to prove everything – you need to show the idea makes sense and that you’ve started spotting risks. By the final chapter, the FDA wants a story backed by hard data: test reports, usability studies, and labeling that states only what can be proven.

Companies often get tripped up by trying to make bold, late-stage claims with only early-stage evidence. The trick is to keep your claims and your data in sync, so when you finally file, the package feels complete and credible.

Early Development: Feasibility & Concept

In the feasibility stage, no one expects a mountain of paperwork. What matters is demonstrating that the basics hold together. Are your intended use statements narrow and realistic? Have you started identifying hazards, environments, and users? Do early prototypes show that the core functions are technically possible?

This is also the perfect time to run some formative usability checks – watching real users interact with rough models can surface issues long before they’re baked into the design. And if you’re not sure about your claims or test approach, a pre-submission (Q-Sub) with the FDA can give you clarity and prevent wasted effort later.

Mid-Development: Design Inputs & Verification

Once you move past concept work, the bar goes up. At this point, you need to turn needs into design inputs – measurable specs that can be verified. And you can’t just make them up; each input should trace back to a risk, a standard, or an absolute clinical requirement.

Verification is where the real testing muscle comes in. Bench work becomes more formal, and biocompatibility studies may be necessary. Additionally, if you have electronics, EMC and safety testing are expected. Software? Now you’re into structured verification and cybersecurity documentation.

Even though the FDA won’t see this until submission, they expect that clear traceability chain: requirements → tests → results. Missing links in that chain are one of the fastest ways a submission can grind to a halt.

Late Development: Validation & Labeling

As you approach market readiness, the focus shifts from specifications to real-world use. FDA wants to know that your device not only works in a lab but also performs safely in the hands of intended users.

Validation often includes summative usability studies, where representative users perform critical tasks under realistic conditions. If your claims extend beyond what can be proven at the bench, this is also when clinical evidence may come into play.

Labeling becomes a central issue. Instructions for use, warnings, and marketing language must align with what you have validated. Overstating claims (even subtly) can derail your submission.

As you get closer to market, the focus shifts. It’s no longer just “does the device meet specs?” but “can real people use it safely and effectively?” That’s where validation comes in. Summative usability studies with representative users, realistic conditions, and critical tasks take center stage.

If your claims go beyond what bench data can prove, this is also when clinical evidence may come into play. And don’t underestimate labeling. Instructions, warnings, and even marketing language need to line up precisely with what you’ve validated. Overreach here is a classic cause of late-stage delays.

Human Factors Throughout

Usability isn’t a box you check at the end; it runs through the whole process. Early formative studies catch risks. Mid-stage work integrates fixes. Final summative studies confirm that users can actually operate the device safely. The FDA expects to see this progression documented. Treat it as an afterthought, and you’re almost guaranteed a redesign when you can least afford it.

Common Pitfalls

The same mistakes keep reappearing. Teams over-promise early with claims they can’t support. They skip formative studies and only uncover usability issues when it’s far too late. They conduct studies without FDA feedback, only to discover that the data won’t be accepted. And they let labeling creep into promises that their validation can’t back up.

FDA expectations scale with your stage. Initially, exploration and discovery are sufficient. Mid-stage is all about proving specs with traceable evidence. Ultimately, validation and labeling take center stage. If you build your package with those shifts in mind, you’ll walk into submission with confidence and avoid the endless cycle of do-overs.