The Need for an Assumptions

Lean UX is a process where the core objective is to focus on obtaining feedback as early as possible so that it can be used to make quick decisions on how to deliver a satisfying experience. If we want to apply lean UX, we need to adapt to the agile technique. The core of the agile technique is teamwork. While developers work in rapid iterative cycles, designers mimic these cycles to ensure that data generated can be used in each iteration. The first on the move are designers: through brainstorming they come up with an assumption that sounds reasonable enough, and after they agree that the topic is well covered, they test their assumption.

An assumption is a statement of something that we think is true.

How do we come up with an assumption? Well, let's say if your brain is working properly and you have two working healthy eyes, you can recognize patterns. Patterns are things that repeat itself over and over, and if we observe things around us well enough, we can recognize patterns and take advantage of them. Let's suppose that people in your town are old and they complain how everything is far and they need half a day just to buy their groceries. So, for now, we know we have a problem and people are willing to find a solution. In the process, you generate answers to certain questions that form your assumptions.

Typical questions might include:

Who are our users? What is the product used for? When is it used? What situations is it used in? What will the most important feature be? What’s the biggest risk to product delivery?

First of all, we need to talk with them about their problem, encourage them to talk more about it and try to stay focused. Only then can we build an empathy towards the problem and have a clear picture. If you can't build (feel) empathy, you will probably fail. Focus will help you channel your thoughts deeper into the subject and unlock all the questions you need to know concerning your solution. Once we have the answers, only then we can assume.

We assumed that the main problem is the distance between a shopping center and older people's homes. If we want to test our assumption we need to build a prototype which can be applied and tested. The prototype can be anything but during the first phase, the best approach is pen and paper. Sketch a few ideas, and then ask your users what they think about your solution. Be careful about their feedback, and make sure they are telling the truth. You can apply the "Mom test" which we will be addressed later. If the assumption passed and you have a green light, you can start the development of a real solution. If not, you should test another assumption or test the same assumption but with different inputs.

Once we have assumptions, we can create a hypothesis. There’s a simple format that you can use to create your own hypotheses, quickly and easily.


We believe that delivery service from the shopping center will save older people's time. It will make older people's lives happier and easier. We will know if our hypothesis is successful if the number of orders is larger than half of the number of older people living in town. We will keep track of the numbers each day for the following 2 weeks.

We establish a belief and explain why and who it is important to. Then we move on to what we expect to achieve. Finally, we determine what evidence we would need to prove that our belief was true. If we find that there’s no way to prove our hypothesis – we may be heading in the wrong direction because our outcomes are not clearly defined. No evidence? Then it’s time to drop the idea and try something else.

Don't be afraid of talking to strangers, you will find out that most people will help you and even want to be engaged in further user testing. If you're afraid and feel uncomfortable when approaching people, find a way for them to approach you. Your job as an UX designer is to talk to strangers, so... you know, just do it.