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Eight Essential Prototypes: The Nesting and Stacking Approach to Product Development

The layers of work that go into designing an innovative product are like the layers of a Russian nesting doll, with the smallest doll representing the core vision. Its shape defines the shape of everything that comes next.

While the final product appears to stand on its own, it’s actually buoyed by tiers of development. These include rounds of prototyping and testing.

We use this analogy to help clients digest the idea-to-product process. The nesting and stacking approach helps people picture where to start and what comes next — and to remember to always keep the vision at the center.

Coincidentally the typical set of Russian dolls consists of eight dolls, matching up with product development’s eight essential prototypes.

Here are those eight:

Mockup
Proof of Concept (or Proof of Principle)
Concept
Alpha Prototype
Beta Prototype
Engineering Validation Test
Design Verification Trial
Production Unit

Mockup: Verify Your Vision

Most people think the core of an innovative product is its new science or engineering, but it’s actually the product vision.

And while it might be exciting to jump right into the technical aspects of a new product, the first, most important step is to make sure your vision resonates with your users. This is how you know it’s worth pursuing.

The mockup should be simple, like a storyboard or a cardboard representation — whatever you can create to express your vision, gauge reactions, and test assumptions. We often talk about “level of resolution” for a prototype and this early stage is when everything tends to be low-res. The mockup is quick, cheap, and dirty, and uses proven technologies, process, and tools to tell the story of the product experience.

The mockup should be simple, like a storyboard or a cardboard representation — whatever you can create to express your vision, gauge reactions, and test assumptions.

To validate their idea, the makers of Google Glass made a mockup using all off-the-shelf equipment except for the single piece of glass that projected light into one of the user’s eyes. The point was to prove that light could be projected into someone’s line of sight without them falling over. More complex prototypes, created to prove computing power could be reduced in size and worn, came later.

At this phase, you want to ask big-picture questions: Is this the future you want? Will this make the world a better place? Will the future be better with, for example, e-readers, smartphones, bike-sharing, space travel? Is it a good thing for the world? For the brand?

Eight essential prototypes: how product development is like a Russian doll

Proof of Concept (or Proof of Principle): Does the Technology Exist?

If the answer to all of these questions is yes, then it’s time to look deeper into the technology with a proof of concept, or proof of principle. This is how you’ll determine if the technology exists and if it’s available at a price that will work for your product.

This is especially important for technology-centered innovation because you’re looking to do something that’s never been done before — whether that’s reconfigure a product, design something lightweight and compact, or create a new medical device.

The proof of concept doesn’t look or feel like the final product — it exists to test the technology.

When we worked with Phlex to develop EDGE, a goggle-worn fitness tracker for swimmers, our proof of concept was a printed circuit board with a buzzer motor for haptic feedback that we tucked under a swim cap to test in a pool. Once we determined the motor’s buzzer length and vibration could be felt on a swimmer’s temple while submerged, the product was all systems go.

If you can’t prove the concept, it might be that the technology doesn’t exist yet or hasn’t come far enough down the cost curve to be viable for your business. If you’re really committed to your vision, you might hold onto it and revisit the technology periodically.

Concept Phase: Which Features Resonate with Users?

Once you’re sure the technology exists and it’s available at a price that makes sense for the end product, you can add another layer.

Start to generate concepts and consider which features your product will have. This is the first time you’ll work on the product’s form, look and user experience: Is it going to be red or blue? Will it have a touchscreen? What’s the workflow?

This is the first time you’ll work on the product’s form, look, and user experience.

In some cases, you’ll want to build a physical form to get a sense of the weight, feel, and shape of your idea. But if you’re developing something people are familiar with, like sneakers for instance, you might only need to create sketches.

You’ll want to talk to users about your concepts to get their feedback. If you’re not sure how many to create, four to six is a good number.

Eight essential prototypes: how product development is like a Russian doll

Alpha Prototype: Your First Integrated Prototype

Now you know how the product works (from the proof of concept), and feel and function have been determined (from the concept). You finally get to build a fully integrated prototype that looks and acts like the final product. This is when it gets really fun, because you’re making something you can actually use in the real world.

The point of the alpha is to determine if the engineering works and stays true to the concept. This is the first time the engineering has to conform to the shape of the vision. Do the systems work together? This will be the first time various systems come together, so you might get some strange, unexpected interactions.

The point of the alpha is to determine if the engineering works and stays true to the concept.

You’ll most likely use prototyping techniques to speed up the process here. For example, you might plan to die cast a part eventually, but for the alpha, you won’t go through tooling. Instead, you might machine the parts out of aluminum. The compromises you make for speed at this point help you get further along, but they won’t be suitable for a production run of hundreds or thousands of units.

Beta Prototype: Preparing For Manufacturing

If the alpha prototype performs as intended and in a way that you can be sure will satisfy customers, you’re ready to advance to the beta prototype. This prototype is all about manufacturing — finding the vendors you’ll use, understanding how you’re going to make each part, and determining who’s going to make it.

If you’re working on a technologically innovative product, you almost always have to innovate the supply chain, too. That might require traveling from factory to factory to find someone who knows how to make specific aspects of your product. And you may need to change the design a bit in order to make manufacturing possible.

Eight essential prototypes: how product development is like a Russian doll

Engineering Validation Trial: Your Product’s Pilot Run

The last three phases of prototyping are all about bringing up the production level. You know what the Russian doll looks like, but you’re adding the layers that make it bigger, more detailed, and polished.

A lot of people consider the Engineering Validation Trial (EVT) like a pilot run. This is where you hand everything over to the vendors to see if the product can be manufactured as you envisioned — and at the necessary price.

You might produce anywhere from five to 1,000 units. If your supply chain seems in order and the hardware is working as expected, you can move on to Design Verification Testing (DVT).

Design Verification Testing: Freezing the Design

Now you’re ready to put your product through final, real-world testing. You’ll verify if it’s durable enough to withstand its environment and complete any certification testing.

If the units pass the battery of tests, design is frozen, and you can finalize your statement of process — the document that explains step-by-step how the product is put together.

Production Validation and Testing: The Final Layer

Last but not least is Production Validation and Testing (PVT). This is the final trial run for the factory. You want to find out how many products come off the assembly line in perfect condition and how many need to be reworked.

These units should be perfect and fully packaged. At this point all the finishing touches are complete, and if the product passes the required testing, you can begin shipping units.

Eight essential prototypes: how product development is like a Russian doll

Shaped by Layers Of Work

Finally, your Russian doll is complete. From the outside, it might look like just one product, but it’s been shaped by layers of work. Beneath the surface, every product contains lessons learned at each phase of prototype. And if you’ve done things right, your final product will resemble the idea at the core of your innovation.

From the outside, it might look like just one product, but it’s been shaped by layers of work.

Prototyping is not an exact science — and from product to product, prototyping paths are never identical. Always keep in mind the whole idea behind prototyping — to test and validate your vision — and let that guide you. The goal is to make the lowest-resolution prototype you need to answer the questions you have at each development phase, and to ask those questions and get feedback from end users at every stage.

If you’re curious about other approaches to prototyping, check out The Six Prototypes Every Startup Needs to Make and 9 Considerations for Planning User Research Prototypes.