The 80/20 rule – The vital few and the trivial many

Whether it’s early in the design process or you’re working with an existing application the 80/20 rule is invaluable in helping you determine what areas of a product should be focused on and what areas should not.


First, what is the 80/20 rule? The 80/20 rule was first attributed to Vilfredo Pareto, an Italian economist who observed that 20% of the Italian people possessed 80% of the wealth.

A few additional examples:

  • 80% of a company’s revenue comes from 20% of its products.
  • 80% of a product’s usage involves 20% of its features.
  • 80% of errors are caused by 20% of the components.
  • 80% of a town’s traffic is on 20% of its roads.
  • 80% of innovation comes from 20% of the people.
  • 80% of progress comes from 20% of the effort.
  • 20% of workers contribute 80% of the results.
  • 20% of bugs contribute 80% of crashes.

For further reading on this principle see

How does this apply to application design? 

In the case of software, if the vital 20% of a product’s features are used 80% of the time, design, research and testing should spend time focusing primarily on those features instead of those which are used on 20% of the time. In fact, if you want to save a lot of time and energy simply focus on what is most important to a project, the 20%. This simple rule is very universal and can be applied to many areas of life but for our case let’s focus on how it relates to product design.

An example

Let’s take a look at the iTunes Store app on the iPhone, an app that lets users browse music, movies, tv shows and more from their iPhone. It isn’t by chance that the tab bar is designed the way it is, with Music, Movies and TV Shows receiving much more prominence than what’s found under more. It’s also likely informed by data and a conscious choice that the product team has made for the user that Audiobooks, Tones and Downloads are less important and thus it’s ok to place them under the more tab.

 80-20 Example


The basic points:

  • The vital 20% are Music, Movies, TV Shows and Search
  • The trivial 80% are Audiobooks, Tones, Genius, Purchased, Downloads and all of the their subcategories.


  1. Don’t spend 2 hours on a single design, instead make 4 layouts at 30min each and test them with real users.
  2. Don’t spend an equal amount of time on each feature of your product, instead spend 80% to 90% of your time making the vital few excellent. Doing this alone will make your product standout and keep you out of the “features for features sake” race with competitors.
  3. Don’t spend 2 hours designing something as a reaction to a customer feature request, instead spend 20 minutes brainstorming whether or not it’s essential. If it turns out to be, apply point #1 and test the rough ideas with real people.
  4. Always ask the question “what’s vital and what’s trivial?”. Asking this simple question this will not only help you clarify the problem but also simplify your product.

Have you found the 80/20 rule effective in your own design process? If so, how? I’d love to here from you so please leave a comment or send me an email!