Prototypes play a central role in UX design. What do we mean when we talk about a prototype? Well, Bill Moggridge, cofounder of the prominent design firm, IDO, described a prototype as a representation of a design, made before the final solution exists. And throughout the course of a UX design project, you'll typically create many prototypes on the way to producing the final design solution. So why do we prototype? Well, there are a number of reasons that we prototype in UX design. One is reification. This is a term that means to make something real or make something concrete. When we prototype, we make our design ideas concrete, so that we can test them out and figure out if they are going to work. We prototype to support Reflection. So by making things real, we can reflect on whether they're meeting the design goals that we have or whether they're taking us in a different direction. A critical role that prototypes play is facilitating communication. So by making something concrete, by embodying it, we can then bring other stakeholders into the conversation, to figure out if the design idea is going to work. And prototypes facilitate assessment, which is critical in the UX process. By creating embodiments of our design ideas, we can use them in user testing, or get feedback from users, as a way to determine whether they're going to satisfy user needs. Prototypes can take a lot of different forms, so that notion of a representation of design, can really mean a lot of different things that we might produce during a UX design process. Ranging from just a verbal description of a design idea, to a sketch or a toryboard. Or a flow diagram, to a physical model, a video, a specification. It can mean lots of different things. But usually in UX, when we use the term prototype, we're talking about a representation of the system as it will be experienced by end users. And we typically produce prototypes at multiple levels of fidelity, from low fidelity, to middle fidelity, to high fidelity prototypes, as the design process progresses. And typically, in a UX design process, we will be increasing the fidelity of our prototypes over time. So starting early in the process, we'll produce low-fidelity prototypes, which are very cheap to produce, but don't really represent what the system will look like in the final version. As we progress farther, we might produce prototypes of increasing fidelity. So mid fidelity and then high fidelity prototypes, as we go closer to the end of the design process. And one of the reasons for this, is that the cost of producing each of these prototypes is going to increase. And we want to make sure that we've worked out as many of the problems and as many of the design ideas as possible, while working in a cheaper medium, before progressing to things that are going to cost more, require more effort to produce and box us in more in terms of the design decisions that we're able to make. So let's go through these different types of prototypes. So a low fidelity prototype is a prototype that we create to address the functionality of the system, to make sure that the system does all of the things that users need. The basic organization of those functions, how you get from one function to another, how they're integrated. And the task flow and coverage, so how do you actually support the tasks that users need to do. And are we supporting all the tasks that they need to do? At the same time, low fidelity prototypes ignore things like graphics, like the colors and fonts that are going to be used. They don't involve any programming. They're often made on paper, so that they can be created cheaply and thrown away when they're not needed anymore. And they don't use real data as a result. As we progress through the design process, we'll need to resolve some of these issues and so we'll move on to other forms of prototypes like mid-fi prototypes. So these prototypes would address all of the concerns that lo-fi prototypes address, like functionality and task flow, but start to also look at concerns like the layout. How specifically are all of the different fields and controls going to be laid out. They might start to address some of the issues of interactivity. So how does it actually feel to interact with the system? And how do you navigate from one part of the system, to another? Still, at this point, we would be ignoring things like the graphics, the specific fonts, the colors, the images. There would be little to no programming involved, depending on the tools that are used and again, we would not really be interacting with real data. We would be using fake data to fill in for data the system would actually use later. And then, towards the end of the design process, when we're pretty sure we have the basic idea of the design right. we would produce high fidelity prototypes, which would tackle some of these concerns that we haven't addressed in the mid and low fidelity prototypes, like graphic design, some more interaction details, like maybe animations. And more realistic data that would map what users would actually be interacting with. Still, a high fidelity prototype is not the final product. It would probably not involve the backend programming that would be required. And it might not have complete functional coverage. It would be focused on the task that that particular prototype is opposed to accomplish, whether that's to support a user task, to support communication with stakeholders and so forth. An article by Lim, Stolterman and Tenenberg, introduces the economic principle of prototyping. They say that the best prototype is the one that, in the simplest and most efficient way Makes the possibilities of a design idea visible and measurable. And this can be applied in the design process, by choosing the prototype that is most appropriate for the phase of design to answer the questions that are critical at that time. So early in the process, you're concerned with functionality and task coverage, than you're less concerned with the details of how it's going to look and feel. Later in the process, after you've established the basic functionality, you're going to be more concerned about those issues. And that's why we progress through different levels of fidelity as we prototype. The main reason that we do this, is we want to avoid premature commitment. Which is investing resources like time and money and design ideas that are going to turn out to be a dead end. When we do that, not only do we waste money and effort potentially exhausting their project resources and running out of time, where we might end up being stuck with a bad design or a design that isn't as optimal as it could be. But also, we end up investing in such a way that makes it very hard for stakeholders to let go of the ideas that have been developed and invested in. So it's difficult to let go of those cognitive and emotional commitments that stakeholders make. Once they've invested significant time and resources into a particular design direction. By focusing on low-fidelity prototyping early in the process, you maximize the number of times you get to refine your design, before you commit to code or manufacturing or whatever it is that you're going to do, to produce the product and for distribution. Low fidelity prototyping uses lightweight materials that quick, cheap and easy to change. Unlike software or hardware. And our friend Bill Moggridge said of low fidelity prototypes, that they are not precious and therefore invite more honest critique. So people are more willing to give honest and open feedback on something that they perceive as not being finished or not being final, than they are when they see something that looks like a lot of work has been put into it. How does prototyping fit into the UX design process? Well, before you can build a prototype that reifies your design ideas, you need to go through the process of first assessing current needs and understanding the design problem that you're trying to solve. Establishing guidelines and constraints for what a good solution would look like, and developing things like personas, scenarios, user stories, requirements and so forth to guide the design process. You also need to go through the process of designing solutions through ideation, sketching, selection and synthesis. And after developing a prototype, you're going to use it to assess whether you're on the right track or not. And you might do that through user testing, or through inspection methods, or just through getting feedback from different stakeholders. And then after that assessment, you'll go through subsequent design processes and more prototyping and continue around this cycle, until you're satisfied with the product. So to sum up, prototypes play a central role in the UX design process. They embody design concepts to facilitate our ability to think more clearly about them. Communicate with stakeholders and get feedback and use them in assessment methods that come from UX research, like user testing and inspection methods.