How to reduce user error while performing an irreversible action?

Question

I have a control which manages the retention period of an email archive shown below.

The customer is able to set a retention period of years and months. The max period is 10 years and the min period is 12 months. Reducing the period can possibly destroy emails kept in the archive. For example, reducing the Retention Period from 10 years to 4 years, will destroy all mail that have been in the archive for more than 4 years.

Feedback I have gotten on this control suggests the following:

1. The behaviour of the control is not clear enough, which may cause mail to be mistakenly destroyed;
2. The control is too easy to use, and thus it's too easy to make a mistake.

Can anyone offer improvements to the design of this control?

Answer 1

Sometimes stress is good

Reducing this period is a big deal. Not something that should be done without careful consideration. Sure, users should be paying attention and carefully consider the actions they're about to take. But let's face it, we all get rushed or fall asleep at the wheel from time to time. And we do stupid things.

Compound our natural tendency to go into autopilot with the fact that many applications today have fairly painless ways to undo actions. Maybe not for something as big as you're proposing, but users have been mentally conditioned to expect a safety net (as they should).

So you need to create an appropriate level of stress around completing this action. Force the user to think twice and really spell out what's about to happen. Then require a confirmation before continuing.

Here's a quick mock of how I might handle it.

Answer 2

I agree with the feedback that the behaviour of this control is not clear enough to the user. A description of the control's behavioiur does appear alongside it, but a user still might miss it or actively choose not to read it. You should work on making this information more prominent in the UI.

I don't agree that the control is too easy to use, as the ease of use of the control is not a problem. The challenge you are faced with is whether or not the design does enough to reduce the user's ability to make a mistake they may regret. Potentially destructive actions should require the user to provide confirmation, to prevent careless mistakes. Common examples of this pattern are the prompts we get before emptying the trash in Gmail or closing an unsaved Word doc.

Takeaways

1. Make the description of the behaviour more visually prominent.
2. Employ a confirmation popup and detail the impact of the change within.