Mistake proofing in design
Empowerment vs Discretion
With modern technology and interaction design techniques, we have greater control over more actions than ever before. The immediate example is writing this post. I can undo any letter, word, sentence or paragraph I write. What’s more, drafts and revision history are being auto-saved in the background. All my actions are reversible and restorable. I only need to focus on writing.
There is no risk — only return.
Welcome to the power of Undo.
The ideal is to avoid errors in the first place. The classic design example are power plugs that match sockets. There is only one way — the correct way — and therefore no possibility of error. But if we cannot avoid from occurring, the next best option is the ability to undo.
I visualize our ability to undo along a spectrum of reversible, recoverable and ‘non-undoable’ actions. I categorize some popular examples using this ‘prism’ and reflect on the wider interplay between empowerment and undo-ability.
‘Mistake proofing’ is a key element of good design. In his book Designing the User Interface, renowned expert Ben Shneiderman outlined eight golden rules of interface design. Of this, one was permitting easy reversal of actions. A related design concept it that of ‘forgiveness’ — which to define concisely, centers on making actions reversible and recoverable.
Design should help people avoid errors and minimize the negative consequences of errors when they do occur — Universal Principles of Design (Lidwell, Holden & Butler, 2003)
Reversals are classic connotations of Undo. Through word (Undo), command (Ctrl+Z) or icon ( ↶), we can instantly recognize a facility to reverse the immediately preceding action(s). A related cousin, the backspace button, also helps reverse actions by allowing us to erase erroneous entries. Money-back guarantee is another example of reversals. We can buy something, and provided it is within the stipulated store policy or law, can also return it — reversing the transaction in terms of products and money. The rewind button on a cassette player is the nostalgic reminder of (literally) reversing the current state of play. Sometimes, physical products come with corresponding ‘antidote’ products. Pencils with eraser caps are the classic example. The specially designed eraser can ‘undo’ the imprint left by the graphite tip.
Reversals are not always complete. Sometimes only partial reversals are allowed. For example, some software, like default Windows Notepad only allows one undo action. Reversals come full circle though. The ultimate convenience is provided by the Redo button, which allows us to undo the undo.
Whether full or partial, undo or redo, reversals empower us with the comfort that our action(s) can be reversed with no consequence.
Recovery is another type of undo, except that it usually takes the proverbial ‘scenic route’. A literal example is when we enter the wrong on-ramp while driving. Most modern motorways have another off-ramp immediately close-by to allow us to re-enter the motorway flow. The route is a bit longer than if we’d not have strayed at all but the end result is a seamless ‘undo’ of our mistake, albeit with a tiny ‘penalty’ to pay in terms of time and distance. Auto-save is another ubiquitous example. I write this post fearlessly knowing that Medium is automatically saving a draft and revision history.
Like reversals, sometimes only a partial recovery is possible. Good design anticipates the need for maintenance. The cleaning kit that comes with your new sofa or floorboard, is an example of a product that is supplied to undo the effects of wear and tear. It will never make the sofa or floor new again, but will keep it as close as possible to the original.
Recovery options enable us to negate an undesirable outcome with a relatively ‘negligible’ penalty.
The Non-Undoable (Real life)
When we can undo an action or transaction, we conquer risk and operate with near invincibility. We can control change and hence feel empowered. This empowerment, however, is limited to human-product or human-service interfaces.
Undo does not transfer to the (most important) realm of ‘real-life’ interpersonal human interactions.
There are two things that cannot be taken back- the sped arrow and the spoken word. ― Jane Casey, The Missing
Reversibility is not a panacea. Nowadays, a hallmark of good service is the ability to buy “risk-free” i.e. return if not satisfied. This is great and very useful facility. But are we getting overly dependent on it? When we expect everything to be un-doable, are we unconsciously being encouraged to “do first and think later”?
And what happens when this habit slowly creeps into “real life” social interactions?
In real life interpersonal situations, there is no Undo button. In real life, undoing carries a penalty in terms of time and effort; and uncertainty in terms of outcome.
The power to undo is convenient. It has increasingly become an ‘expected’ feature of designs that we love. True empowerment though is about discretion — about understanding that some actions cannot be undone, and, counterbalancing those with forethought.