Stop showing people your prototypes- it’s just not right. Sure, they’ll tell you they like them or ‘Yes, I would be ‘highly likely’ to use that’, but that’s just because they don’t want to make you feel bad and, really, they just want to move on with the rest of their lives.
I know- you like to make prototypes. So do I.
There’s a time for prototypes, but it’s not when you’re trying to test whether a customer might want some new product or feature. For that, I would use a Minimum Viable Product (MVP) which put your subject in a position where they have to decide (on their own) whether they want to express an interest. That might be as simple as clicking on an ad or as substantial as cutting a check. However, getting some poor subject to tell you what you want to hear isn’t a valid expression of interest.
Where are prototypes useful, then? Prototypes are great for testing usability, particularly in the exploratory phase when you should be considering a lot of alternatives. In the context of product development, I’d say they’re a great fit for item #3 in the diagram below:
If you buy the summary above as a roadmap for disciplined product creation, then you can see that before you worry about usability, it’s important to #1 talk to customers and see what’s really on their A-list and then to #2 use product proxies to test how motivated they are to use or buy the the proposition you’ll offer. This is the key thing: if the user is not that motivated by your proposition, you don’t need to worry about testing usability with prototypes. It gets you nowhere. I see a lot of beautifully executed apps that no one wants. While good usability contributes to customer wins, I see it chronically under-invested in relative to motivation.
However, let’s say I’m building an interface for students to use in turning in their assignments for class. and I wanted to test its usability. Then I would control for motivation with a prompt to the the test subject like ‘Would you show me how you would turn in this assignment?’. In this case, I’m not trying to test whether the subject wants to turn in their assignment- I want to know how easy the interface I’m putting in front of them makes it for them to turn in an assignment. For this, prototypes are a great fit.
This distinction between motivation and usability is important. You should know where you’re focused and which you want to test. MVP’s are great for testing motivation and you’ll get the most out of them if you know what specific proposition you’re testing. Usability testing is well understood and productive when you likewise know specifically what affordances (or user stories) you want to test. For understanding the relationship between motivation and usability, I like BJ Fogg’s ‘Fogg Curve’:
Ability (the inverse of usability) is on the x-axis and motivation is on the y-axis. If you imagine a point in the upper left, that would be something like a cure for cancer where you really want it and even if it’s hard to get you’ll persist. If you imagine a point on the lower right, that would be checking Facebook where you’re only somewhat motivated but if it’s really easy to have a look, you will.
In conclusion, when and how should you show someone a prototype? You should show it to them when you want to test usability and you should supply a specific goal (to control for motivation) and watch what they do (vs. say) as they try to achieve that goal with the UI you’ve put in front of them.