The Pareto Principle in UX design

Understanding the Pareto Principle is useful for any company that wants to focus efforts on those actions and areas that will bring the most rewards.


Lia Crupi

UX / UI designer

How many features in your favourite software do you use on a daily basis? A handful? How about your favourite website? Have you read all available pages or do you visit the same 3 pages every time? Do you use all the functionalities of your social app, or do you just press the “Like” button most of the time? Examples like these can continue endlessly and are pretty much the norm. We can attribute these behaviours to the 80/20 rule, otherwise known as the Pareto Principle.

The Pareto principle states that, for many events, roughly 80% of the effects come from 20% of the causes.

Vilfredo Pareto was an Italian economist who noticed in 1906 that 80% of Italy’s land was owned by 20% of the population. This relational effect is not limited to economic issues, but extends to everyday life, both online and offline (I bet you tend to wear just 20% of your clothes 80% of the time).

An apartment plant needs a small pot of soil (20% causes) to grow tall (80% effects). Also, take care of the roots (20% efforts) and you´ll get beautiful, healthy plants (80% results)

Why does the Pareto Principle matter?

Understanding the Pareto Principle is useful for any company that wants to focus efforts on those actions and areas that will bring the most rewards. For example, developers at Microsoft noted that by fixing the top 20% most reported bugs in their softwares, 80% of all errors and crashes would be eliminated

It's important to note that 80/20 is a rule of thumb and that the actual ratio can be more or less, such as 70/35 or 80/10. However, the takeaway of the Pareto Principle is simple: within any system, be it a company, a country, a webshop or your wardrobe, only a few variables greatly affect the outcome

What are the benefits of using the Pareto Principle in UX?

It doesn’t matter how complex your website or application is, if you dig into user analytics you will find proof of the Pareto Principle in action. Being aware of this effect is a powerful advantage for any company or brand!

You will find, for example, that a few functionalities (or pages) receive the majority of users’ time. Following the logic of the Pareto Principle you can be quite sure that focusing your resources on these few, essential features you will improve users’ ability to find relevant content.

Focus your efforts on that 20% of your product´s functionalities that can bring 80% of the results.

How to identify your 20%

As Arin Bhowmick, Vice President and designer at IBM, has said, the unavoidable truth is that we have finite resources to figure out an infinite amount of problems. Considering the Pareto Principle will help you figure out what matters most, allowing you to invest your time and effort into the key areas that will help deliver the greatest impact.

1. Analytics

As we have mentioned, whenever you have quantitative data about your website – for example a Google Analytics report – you may be able to observe the Pareto Principle. Simply identify the most important and most frequently used elements on your website and focus your efforts on the features or pages that bring the most results.

2. User research

You can also observe the Pareto Principle when you run a user research. User research helps understanding user behaviors, needs, and motivations through observation techniques, task analysis, and other feedback methodologies. From the results of a user research you are able to gather information on your target group’s needs and goals, as well as identify the top percentage of your product’s usability issues and feature gaps. With this precious information, you can focus your attention and money on fixing the features that are really bringing value to your target groups.

Jeff Sauro, the founder of MeasuringU, said it quite clearly:

“The principle was startlingly accurate. Our research showed that 18% of our core product areas were causing 83% of our clients’ frustrations.” — Jeff Sauro

3. User test

Observing how people use your product through user tests can reveal functional barriers which everyone on the design team might be unaware of. Having an in-depth knowledge of the digital product often makes designers and product owners blind to issues, but observing real-life users’ behavior with your product gives you a clearer idea of their focus and priorities.

Take away

While it can not, and should not, be the solution for every problem, basing decisions on the Pareto Principle can be very effective in user experience work. Wherever there is data that can be quantified or user behaviours that can be observed, there’s a great advantage in focusing effort – and money – on the areas of your work that bring the most results.

But remember, don’t worry too much about finding the perfect 80/20 balance. Instead, look to find where a small number of items account for a disproportionate amount of results.