From a Lean point of view, bad UX is static, hindering the signal. If you want to test whether people are interested enough to sign up for your new product idea, spending a little time thinking about the UX means that your results will actually reflect people’s interest; not whether they can find the sign-up button or if they can be bothered to fill in a long, tedious form.
A handful of users will be able to identify the majority of problems with your product. Even one user will find a large percentage of the issues on their own. Some of the most revealing UX tests that were conducted took one user less than 5 minutes, and at no cost.
There’s a temptation with UX testing to just ask what users think of your site, and if they like it or not, but the responses you will get from this type of testing are not going to provide any specific answers on what you need to change, add, or remove. Also, when you use this kind of vague data, you’re more likely to shape the ‘results’ into the answers you want. Quantitive, observable data is what you're looking for. Don’t ask “Do you like this site?” Instead, ask "On a scale of 1 to 10, how likely are you to use this site?” Avoid asking people if they understand. You’ll only find out if they think they understand. Instead use measurements like the number of seconds it takes users to complete a task, or the number of unsuccessful attempts they make to discover whether they really do understand.
There are various quick and dirty ways of testing without using your actual product. You can make paper prototypes, or turn Balsamiq wireframes into a clickable mock website. You can also upload images of your designs to InVision to make a more hi-fi interactive prototype. People often dismiss these methods, especially paper prototyping, because they don’t look or act exactly like the real website, and people assume this will distract users and distort testing results. But you’d be surprised how quickly users suspend their disbelief and start utilizing the prototype just like they would use an actual website. All of these quick and easy Minimum Testable Products will tell you important things about whether users can navigate through your site, discover features, follow the flow and so much more.
Guerrilla testing is fast, it’s easy, and it’s free. Just catch someone walking past your office, or making coffee in the breakroom and get them to quickly try out the product. Of course, the big disadvantage of guerilla testing is the sample bias. Think about with whom you share your office. It’s usually other people working in tech or start-ups too. Unless this is your target audience, testing with them will not give you all the information you need, and this will often lead you astray. Tech folks are power-users who will often ask for loads more features than your average user. They often love novelty, so they will rave about a cutting-edge gestural interface that will confuse general users. Go ahead and use guerilla testing, but remember to step outside your filter bubble and test your target users. Easy online tools like WhatUsersDo, ClickTest, ChalkMark, Five Second Test and Optimal Sort make it possible to get rapid feedback from different types of users.