Tuesday, December 13, 2011

Easy to Use vs Hard to Misuse

It’s an awful thing to admit, but I think old mainframe green-screen applications are easier to use than slick web applications; where modern web apps have the advantage is that they are hard-to-misuse. “Easy to Use” is very different to “Hard to misuse”. They are two very different things with very different implications for system strategy, enterprise arch, and business requirements.
• Easy to Use: As a regular user or seasoned operator I want to be able to do things effortlessly with a minimum of interruption so that my workflow, thinking, or customer service is not interrupted.
• Hard to Mis-Use: As casual user or end customer I want it to be obvious to me how to accomplish normal tasks so that I can complete teh activity with a minimum of frustration and get on with my day.

I’d illustrate with calculators. I know I over-use the calculator similes; but I’m a geek and if you’re reading this chances are you are to.

Of my four favourite calculators in my house, I consider them all “easy to use” – but in really different ways:

  • My HP12C financial calculator is simple for complicated calculations (Thanks to RPN) or financial calculation (Thanks to dedicated functions; but my wife can’t even use it to do simple arithmetic. It’s very easy to use – it’s just very easy to misuse it as well as normal people don’t think in Reverse Polish.
  • My Blue HP is simple for my wife as she just types in the calculation, or for me when I’m learning new techniques as it displays everything on screen. It’s very hard to “misuse” this calculator as it feedbacks everything you’re doing to you, and uses the “standard” mental model of arithmetic.
  • My Casio Calculator watch is simple for use on the go; despite the numbers being tiny and a lack of dedicated functions.
So the things I’d like to point out from this:
  • Being hard to misuse generally comes from the systems metaphor matching to users mental model with the minimum of differences (My wife think of 1 + 1 = 2, as does my calculator.)
  • Being hard to misuse is helped by copious user feedback – that is useful for keeping people calm that their operation is on track but may not be absolutely necessary (think confirmation screens, double entering passwords, etc)
  • Being easy to use generally comes from dispensing with the feedback and cues and exposing only the information the user needs to know (Simple, powerful inputs. Command lines, etc)
  • Being easy to use is enhanced by coming up with a different metaphor (Instead of “1 + 1 = 2” you get “1 push 1 +”) whose benefits are only obvious with prolonged usage.
  • Easy to use is all about context. What makes my calculator watch easy is the tiny keys and screen which give portability – but in a desktop calculator this would be a major fault.
When you get it really right you come up with something that is both Easy to Use and Hard To Misuse. I think Google Mail is a great example. The core metaphor of “tags’ is simple and understandable, but can be very powerful once you work at it. It’s interface gives you a lot of feedback on what’s going on – but in a clear way that guides you through. It provides lots of keyboard shortcuts– whilst giving novice user cues.

No comments:

Post a Comment