Pareto Principle

Synonyms: 80/20 rule, the Law of the Vital Few

The Pareto principle is also called the 80/20 rule. It states that 80% of the effect of any action comes from 20% of the effort made.

For example, 80% of your users need 20% of your features, or 20% of the code causes 80% of errors.


The Pareto principle should be considered as a rule of thumb. After all, it happens that 60% of the result is achieved by 40% of the effort made and the like. In simple terms, a small number of things make a big impact.

Picture by Jose Mendoza

Visualization of Pareto Principle

Who is Pareto

Wilfredo Pareto, an Italian economist, noticed that 80% of Italy's land belongs to 20% of the population. He then found out that the situation in other countries is similar. Despite its origin, this principle can be applied to everyday life, economics, and design.


It is important for a designer to highlight points and functions that users want to see. This requires user experience research. This is where the Pareto principle will be extremely useful. There are several ways to determine the very 20% of the functionality that is often used.


You can track the most used sections and elements of a web page.

Using this data, you can understand how often people use different segments of a particular site and then optimize these particular parts of the page. Thus, the experience that the user gets from using the product becomes simpler and clearer.

Let's consider the work of the Pareto principle using the example of a messenger. The main task of the service is to communicate with people. First of all, through messages, and then calls. Therefore, designers make access to these functions easier and more intuitive, even for non-technologically advanced users.



Usability testing allows developers and designers to understand the feelings of the users who see this product for the first time.


The professionalism of the website creators does not allow them to look at the picture from the right angle and, therefore, highlight 20% of the most used elements and functions. After testing, it will be clear what should be emphasized and which aspects of your project should be improved or simplified.


For example, if the user begins to move the mouse for a long time in some areas of content, it obviously takes too much time to understand the meaning of it. Therefore, it is worth working on the design of this part of the page or rephrasing the text.


Highlighting the main thing based on the experience of designers

In the search for a 20/80 compromise, it is helpful using the existing experience. Analyze good examples of similar projects and feel free to target them.

For example, everyone is already accustomed to a certain order and name of menu items in programs. And no one wants to place the "File – open" or "File – save" functions anywhere other than the upper left corner of the screen.

Consider basic design principles

When designing an interface for a web application or designing a poster, it is worth remembering the things that form the foundations of composition and color. 


For example, place the most important in the upper left corner and then diagonally. This is how a person's gaze moves when learning something new. 

Tips & Tricks

  1. Use Pareto Principle to make better decisions in your work whether you're building a website or software

  2. Put the main effort into the 20 % of tasks that will bring the greatest benefit to your users

  3. Use this principle to prioritize development and address design issues that are important to the user experience

  4. Be aware of sample sizes and other forms of data that can redefine the Pareto Principle in fact


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