Mobile UI design: obey the 90/10 rule

Mobile UI design: obey the 90/10 rule

Summary: The 90/10 rule is based on the years I have covered mobile technology, and the observations I've made of countless users of said technology. A good UX is crucial to get a good customer reception, and the 90/10 rule can go a long way to getting one.

TOPICS: Mobility, Wi-Fi

User experience is a major contributing factor to the success (or failure) of a mobile device in today's highly competitive marketplace. That experience begins forming as soon as the device is removed from its box (OOBE), and evolves over the first few weeks to determine the user's overall perception of how good a purchase was made. Handheld devices are very personal in nature, and the user interface (UI) plays a large role in how well a gadget is received in the market. A good user experience (UX) is crucial to get a good customer reception, and the 90/10 rule can go a long way to insuring a favorable reaction to any mobile device.

The 90/10 rule is based on the years I have covered mobile technology, and the observations I've made of countless users of said technology. I've noticed that if a gadget doesn't grab the user's affection right from the OOBE, it has a good chance of being returned for another device that feels better while used. While the hardware design often attracts the buyer, it is the UX that keeps them.

I have noticed over the years that a typical mobile device user spends 90 percent of his/her time using just 10 percent of the device functions, thus my 90/10 rule. These handful of activities are conducted repeatedly during standard usage of a device, and how well it performs them is vital to make a user feel good about the gadget. These activities vary based on the type of device; a smartphone needs to do calls, email, text messaging and web browsing for example.

It is important for a manufacturer (hardware and platform) to correctly determine the 5 or 6 functions for a given device that the typical user will spend most of her time performing. Make these activities simple to perform, intuitive to a fault (no instructions required) and bullet-proof. That means these most-used activities never fail during standard usage.

The 90/10 rule is a large part of the formula that Apple has used for years, and it's garnered them an outstanding reputation with users. Apple engineers are masters at correctly determining which activities will be done by a typical user 90 percent of the time, and then making those tasks perfect. This is a big reason why Apple's customer loyalty is so high; buyers know the Apple gadget will do what they need it to do, do it well and right out of the box. Sure the more advanced tasks (remember cut and paste?) might be missing at first, but Apple correctly determines what matters and what can be added later.

Gadgets designed with the 90/10 rule in play are invariably perceived favorably by the new buyer. The device simply works as expected, without frustration and right from the get-go. The user feels it was a good purchase and will likely recommend the device to others as a result of the good UX.

You may have purchased a gadget in the past that wasn't built with the 90/10 rule, and lamented it from the beginning. Maybe the device would do sophisticated things well, but one of the activities you did regularly had problems. Frustration quickly mounted and even if you didn't return the gadget to get something else you didn't recommend it to others.

Once a product has been released following the 90/10 rules, the rest of the functionality can be added (or perfected) later. The key is grabbing the customer's loyalty through a great OOBE, and then adding functionality with tasks that aren't done as regularly as the 10 percent in the rule. Sure, critics will sound off about the lack of a given functionality, but it's the buyer you're trying to win over, and you will by following my rule.

Apple is not the only company making gadgets that gets it right, but they almost always do it properly. That's why I use them as an example of how to do it right. You can argue about Apple and its products if you're not a fan, but hundreds of millions of customers understand the value of getting the 90/10 rule right. Over and over again.

Topics: Mobility, Wi-Fi

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  • That philosophy extends to their desktops and laptops as well...

    That philosophy extends to their desktops and laptops as well, and is evident in their adoption and elimination of certain technologies. They were criticized pretty heavily for dropping the floppy drive in favor of USB and CD-RW on the original iMac, but people quickly realized that 90% of us didn't use floppies anymore; especially on Macintosh.

    Likewise with their desktop operating system. Apple has long been criticized for only including a 1-button mouse, but Apple realized that 90% of what you do on a computer can be done with a single click. Despite now including a 5 button mouse and multi-touch track pads, Apple's philosophy hasn't changed: you can still operate every aspect of Macintosh with a single button. For more advanced users, the other 4 buttons are there (or however many buttons you want, really, with a 3rd party mouse).

    The OS X GUI is no exception. It has the user friendly interface Apple is renowned for, but should you want more control or direct input, there's the UNIX terminal.
  • RE: Mobile UI design: obey the 90/10 rule

    So rather than try and include every possible ?feature? it is more important to get the important ones right? Maybe other hardware and software vendors should examine the way Apple designs products, instead of making jokes about them. ;)
  • I understand that this is a Mobile News centric blog

    but did you feel that the 90/10 rule was violated with the Vista interface, James?

    I don't know about your experiences with Vista but I found it rather confusing to "get to where I wanted to go" quickly and efficiently.

    Don't misunderstand, Vista "worked" for me in the sense that it ran the programs installed on it but I just found it confusing to work with. (Just my opinion and experience.)
    • I actually found it easier than XP

      I just had to get used to typing out what I want to find, and use the search box.

      I think it used the 90/10 rule rather nicely, but only after they fixed the search bar to where it didn't take forever to find anything.
      Michael Alan Goff
    • RE: Mobile UI design: obey the 90/10 rule

      I honestly feel that, like Office 2007, it was just change for the sake of change. I have heard from several people that the changes make it harder to use. This fits with my observations, especially in Office 2007. Change, for the sake of change, is not always good.
    • RE: Mobile UI design: obey the 90/10 rule

      @kenosha7777 while I chose to address the mobile space specifically, the rule for good UI is certainly applicable to desktop platforms. Vista was not MS' best offering IMHO.
      • Don't lie

        Nobody here is humble. ^_~
        Michael Alan Goff
  • RE: Mobile UI design: obey the 90/10 rule

    "The 90/10 rule is a large part of the formula that Apple has used for years"

    Really? How do you know this? Can you share with us the other, smaller parts? Competitors would love to know! Of course the next largest part of the formula would have to be good marketing. Quick -- someone tell Apple's competitors to spend more money on ads!

    I would say the "formula" has more to do with tight integration (including ecosystem) and the seamless user experience no matter what the user wants to do. But that may also be wrong since no competitor has been able to copy that either...
    • "Competitors would love to know!"

      "They just don't get it"...
  • RE: Mobile UI design: obey the 90/10 rule

    Like i've always said, the user interface (UI) and how it performs is probably the most important feature of a device. It is important to get that right first, and build upon from there. It forms as the bases of getting the user (i.e. non-geek) warmed-up to using the device. You can always add more features later. Take a look at the iPad as an example. The polish, the fluidness, The natural gestures, the way you effortlessly go from screen to screen and app to app without any hitch, the subtle animation that gives feedback, even the warm colors of the UI plays a part vs cold geeky futuristic tron Honeycomb. Also the familiarity of the iPhone UI is probably what got people excited initially about the iPad. They could imagine the many ways to use it before ever holding the device. <br><br>What I've notice of someone using an iPad for the first time is the immediate positive feedback. They did not yet read the specs, or go through all the features or apps, this positive feedback is a result of a great UI (something you don't see listed on spec sheets). <br><br>Another company that gets the UI is Palm (now HP). Having lots of Ex Apple employees I guess it's no surprise they get UI design. Microsoft is attempting to follow the same 90/10 principles with WP7, lets see how well they do.
  • RE: Mobile UI design: obey the 90/10 rule

    Mostly, I agree with the article, though the 80/20 rule was the first that came to my mind when I read the headline, and I find that 90/10 is kind of an extension to the 80/20 rule with the numbers changed.

    Also, I am not sure if cut/copy/paste is outside the things users do 90% of their time. I may be wrong, and I hope for my sake that this does not come under the 10% of what I do for 90% of my existence :-)
  • RE: Mobile UI design: obey the 90/10 rule

    Great article. The 90/10 principle should be applied for all software development. it's analogous to quality vs quantity. Delivery quality functionality that is rock solid and than add quantity into newer releases. This also plays into Apple's marketing strategy, get users hooked into the product and then charge for upgrades (or make the customer buy the newer product). Worth mentioning is a site called mobileInDesign,, which showcases mobile UI design trends.
  • User validated findings or opinion

    Is this opinion or user validated research?
  • RE: Mobile UI design: obey the 90/10 rule

    Exactly the reason I won't ever have a Samsung phone again, regardless of reviews. I think it's something that a lot of tech-savvy people forget too, that for the majority the UI/UX is of vital importance, not the technical specifications or customisation possibilities (just using a little rooting/cmd line/registry tweak...)
    • RE: Mobile UI design: obey the 90/10 rule

      @obliquewordsmith Oh, and just a little add on, Office 2007/10 is just so much more logical and intuitive than the nonsense of drop down menus and older Office apps. I learnt the new one in minutes and loathe having to go backwards whilst at work.