Sabotaged by Interruptions

Doug Avery, Former Senior Developer

Article Category: #News & Culture

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We work in an interrupted state — between open offices, IMs, notifications, and second screens, the opportunity to be interrupted during a task is higher than ever. 

Even as long as 9 years ago, there was research showing that knowledge workers deal with a surprisingly high number of interruptions. A study of 24 knowledge workers found that they only worked on a single project for 11 minutes before switching or being interrupted. This work concluded that an average day is chunked up into a lot of small periods, and that frequently, workers don’t have control over when those periods begin or end.

The cost of interruptions

Jonathan Spira and Joshua Feinruch estimated that $588 billion a year are lost in the US alone due to interruptions. Why are interruptions so, well, disruptive?

They affect your ability to complete a task

Gloria Mark found that people interrupted from a project not only didn’t return to it until 25 minutes later, but in that 25-minute period, often worked on a third project. 23% of interrupted work wasn’t even returned to on the same day! Interruptions affect our ability to simply finish work on time.

They waste time

In a flow like this, interrupted workers are constantly dropping and returning to tasks, which comes with a cost. In Pragmatic Thinking and Learning, Andy Hunt claims:

Unlike computers, our brains don’t have a “save stack” or “reload stack” operation. Instead, you have to drag all the bits of memory back in, sort of one-by-one. That means that if you are deep into a task (such as debugging) and then get interrupted, it can take you an average of twenty minutes to get back into it.

If I’m writing code to complete a ticket and get interrupted for 30 minutes, when I return to the task I reopen the ticket, reread the code I’ve written, and test it just to figure out how far I got. Worse, if I’m interrupted again, I have to repeat this process — eventually, I’ve spent more time re-learning the work than doing the work itself.

They cause bad decisions

A study in 1999 showed that interruptions had a negative effect on the accuracy of complex tasks. That is, when you’re interrupted completing a complex task, you won’t only take longer, but you’re more likely to screw it up. Furthermore, if the interruption is about a dissimilar task or subject, the effect is even stronger.

I find that in the middle of difficult work, I'm more likely to make snap decisions or respond to emails without really reading them — not necessarily out of rudeness, but because I'm trying to keep the context of the work in mind before I lose too much.

Why do we allow them?

So interruptions are pervasive and expensive — why are they still so frequent? Why can’t we recognize when not to interrupt someone, or how to avoid being interrupted?

They’re about relationships

The reason many interruptions seem impossible to ignore is that they are about relationships - someone, or something, is calling out to us. It is why we have such complex emotions about the chaos of the modern office, feeling alternately drained by its demands and exhilarated when we successfully surf the flood.

— Clive Thompson, NY Times

Interruptions feel good — they're about your personal importance, and your ability to help others. I think most web workers can appreciate the rushed feeling of a launch day, quickly jumping between urgent tasks, and can appreciate the addictive quality that flow can have.

It’s hard to tell good from bad

Jonathan Spira points out:

Not all work is created equal, nor are all interruptions. Many believe interruptions fall into two categories: when I interrupt someone (a "good" interruption), and when someone interrupts me (a "bad" interruption).

When I open up an IM window to bug someone, it's hard to assess whether my request is urgent, important, both, or neither. It's also hard to tell when someone else is focused on a particular task — the assumption is often that if I'm free, they're free, so I err on the side of interrupting.

We create them ourselves

...knowledge workers can be their own worst enemy. In the same survey, when asked how quickly they respond to a new e-mail notification, 55% said immediately or shortly thereafter. Only 35% said when convenient.

Spira's survey also noted that workers interrupted themselves in many cases. Shamsi Iqbal and Eric Horvitz found that disabling email notifications caused some workers to self-interrupt more frequently, monitoring email at the expense of other tasks. I've found that disabling email allows me to get deeper into difficult tasks, but I definitely feel an anxiety worrying that others in the office are having conversations that I haven't read yet.

And sometimes, they're necessary

High-tech workers grumbled and moaned about disruptions, and they all claimed that they preferred to work in long, luxurious stretches. But they grudgingly admitted that many of their daily distractions were essential to their jobs.

— Clive Thompson, NY Times

It's important to recognize that some interruptions are urgent, or come at critical times in our work, and that completely shutting them out could be counterproductive. The unprecedented ability to communicate allows us to quickly react to situations, and in same cases, the reaction speed can outweigh the importance of our other work.

What can we do about interruptions?

Save interruptions for breakpoints

If an interrupted person is allowed to suspend their working state or reach a “good breakpoint”, then the impact of the interruption can be reduced.

— Chris Parnin, Ninlabs

A key to creating opportunities for breakpoints is communicating asynchronously when possible — batch notifications into email, action-oriented IMs, or daily digests that allow interruptees to address them when they’re free.

Create "no-interruption" zones

Medicine and aviation have practices regarding no-interruption zones, and times/places where interruptions of a certain nature were disallowed. The same tactic can apply to knowledge workers, who can create safe spaces by working in private, putting up away messages, and blocking off “don’t interrupt” times on their calendar. Obviously, going into a no-interruption zone also means turning off your own notifications — put the phone in airplane mode, turn off Growl, and disable email updates.

In some offices, moving to a room isn't an option, so I've taken to wearing these guys when I know I need to focus. They're sound-blocking and highly visible, which helps prevent people from interrupting me in-person.


Create policies and norms for asynchronous communication (Rennecker & Godwin, 2005). Train employees to know when and how to interrupt one another (Sykes, 2011). A very effective method of removing interruptions is for employees to communicate with one another asynchronously. Whenever possible, policies that encourage synchronous communication should be modified.
For example, an extant norm of the office wherein emails are returned within one half hour of sending should be discouraged. In its place should be policies where individuals are encouraged to check their emails just a few times today, or only at select times.

— Stacy M. Baer and Larissa K. Barber, PhD,

It takes two to create an interruption, so addressing the problem alone is tricky. If you develop policies and expectations around communication at your workplace, make sure that they’re clear, public, and reinforced in your daily communication.

Interruptions are a difficult topic, because cutting them potentially means cutting interactions with others or leaving others blocked on quick tasks. Moving to a room or putting up an away message can block personal relationships, or prevent creative sparks from forming on a team. Other work suggests that an interruption-prone environment can be ideal, if workers are on the same project.

But, what do you think: As the process of building websites becomes more collaborative and involves more players, how can we balance the desire for collaboration with the need to complete tasks uninterrupted?

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