In this post I will describe the UX “laws” that we should take into consideration when designing our user experience.  These “laws” are really more generalized statements based off of research of user behaviors.  As with any law/rule there are always exceptions and non-believers.  I like to think of them as a guidelines.



Fitt’s Law

What is it?

A model that tries to predict the time and effort to reach a specified target on the screen.  Generally targets that in the corners of the screens are easier to reach and targets that take up more screen real estate are easier to reach.  Also targets that are closer together make are easier to reach.

How this applies to UI design?

Make sure to place important content in areas of the page which are more easily accessible like the corners.  When designing action buttons make them easy targets by making them bigger.  Place commonly used buttons together.

Everyday application

Re-examine the layouts of your interfaces.  Are important items in easily accessible areas of the screen?  Do you have buttons that are commonly used in different parts of your interface.  Remember you want to help guide the user to what is important and reduce the time it takes for them to get to key pieces of functionality in your interface don’t make them scroll across the interface to complete their tasks.

Further Reading?

Fitts’s law – Wikipedia, the free encyclopedia

Usability First – Usability Glossary – Fitts’ Law | Usability First

Interaction Design — When You Shouldn’t Use Fitts’s Law To Measure User Experience | Smashing UX Design (includes when NOT to use/ perils of Fitt’s Law)

Teslers  Law

What is it?

Sometimes referred to Tesler’s law of the conservation of complexity states that no matter what we do every application will have some complexity.  No matter how much you invest in the user experience, it will at some level be complex.

How this applies to UI design? / Everyday application

When designing user experiences we inevitably will be faced with many constraints with the big ones being time and resources.  Looking at the bigger picture if it takes a month to build a piece of functionality to reduce the user’s process by a minute every day would your company do it?  We can certainly run an analysis to figure out the cost of building the functionality and try to determine if it would be worth pursuing. “Whose time is more important to the success of your business? For mass market sofware, unless you have a sustainable monopoly position, the customer’s time has to be more important than your own.” – Larry Tesler.  Don’t pass off the work to your end user.

Further Reading?

Law of conservation of complexity – Wikipedia, the free encyclopedia

The Law of Conservation of Complexity

Hicks Law

What is it?

The more choices we have the harder it is to make a decision.

How thisapplies to UI design?

The more features we pack into a single screen the harder it is for a user to understand what the screen is for and where and how to take on that screen.  To increase usability we need to reduce the cognitive load on the user, don’t make them think hard.  So when you are building you new Fiori app do not put 20 graphs and charts on their dashboard.  While it might look cool all those charts will make it difficult for your users to focus in on what you want them too.

Everyday application

Re-examine what fields are actually needed on your forms.  Look at your interface are there particular pages with tons of links  Show the screen to someone new who has not used it and ask the what it does can they tell what it is used for?  Or is it cluttered with too much information to denote what the purpose of the page is

Further Reading?

http://en.wikipedia.org/wiki/Hick’s_law

http://www.usabilityfirst.com/glossary/hicks-law/

http://uxdesign.smashingmagazine.com/2012/02/23/redefining-hicks-law/


Poka- Yoke Principle


What is it?

Make a process or behavior “error proof”.  For example if you are making a shoe make the shoe in the shape of your foot not in the shape of a circle with the diameter roughly equivalent to your foot length, where would the front of the shoe be? 

How this applies to UI design?

When designing UIs get down to the very minimum required to complete the task.  Try to guide the user whenever possible with visual cues, layout cues, and simple process flows.

Everyday application

Re-examine what your interfaces do you have extraneous information?  Try to remove the ability for users to get to error states.  Use real time feedback when possible don’t make me submit the form before I see that a field is missing.


Further Reading?

Poka-yoke – Wikipedia, the free encyclopedia

Poka-Yoke | you can’t go wrong | The Toyota System

http://blog.teamtreehouse.com/poka-yoke-the-quest-for-mistake-proof-designs

F-Pattern for reading


What is it?

Almost every user that reads in a “F” pattern starting with the upper left corner.  This applies to left to right languages that are read top to bottom.  There are some changes in the orientation of the “F” for readers who utilize languages that are read right to left

How this applies to UI design?

When designing UIs put the most important piece of interface for the user in the upper left corner as that will most likely be fore the first thing they see.  On the flip side do not put the piece of content you want every user to see in the bottom right hand corner as that will be last thing they read.

Everyday application

Re-examine what your interfaces do you have extraneous information?  Try to remove the ability for users to get to error states.  Use real time feedback when possible don’t make me submit the form before I see that a field is missing.


Further Reading?

F-Shaped Pattern For Reading Web Content

http://webdesign.tutsplus.com/articles/design-theory/understanding-the-f-layout-in-web-design/

http://blog.teamtreehouse.com/poka-yoke-the-quest-for-mistake-proof-designs

Sturgeon’s Law


What is it?

90% of everything is crap -lots of applications out there are very difficult to use.

How this applies to UI design?

When designing UIs/processes/ overall user experience think critically.  Its becoming very easy to produce a poor quality product – some even look nice until you use them.  This can also apply to any UX practitioners; focus on only a couple of areas to master there are no UX unicorns our there.  Don’t be afraid to bring in additional resources for a singular aspect of a project.  In my personal projects I try to leverage graphic artists whenever possible to produce a better quality product.  Good products come from collaboration across expertise verticals not a lone Interaction Designer/Visual Artist/Front End Developer/Content Strategist/Product Manager/Back End Developer.

Further Reading?

Five Indispensable Skills for UX Mastery

90% of Everything is Crap, and What To Do About It  |  The Discipline of Innovation

There are some more laws/guidelines/principles out there that one could follow so I encourage you to do more research on your own.  (those include but are not limited to Gestalt Principles of Form Perception, Rule of Seven, Parento Principle- 80/20 Rule)

Also remember that UX design is both an art and science.  It is always evolving and changing so don’t be afraid to try new things.


Stay tuned for the next part in the series..part 7


Part 1, Part 2, Part 3, Part 4, Part 5


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