And it’s gone —The true cost of interruptions
People need roughly 23 minutes to go back to their tasks after a major interruption, but the plot deepens if you’re a programmer. Add at least 10 minutes to the forced break (the minimum amount of time you need to start editing code again) and there you go — that’s a solid half hour you lose whenever someone approaches you. It gets worse if that interruption is planned.
If two hours go by and no one interrupts you, consider yourself lucky. According to an article by Game Developer Magazine’s Chris Parnin, developers lose more time going back to a task after they’ve been interrupted than people working in other industries and the time spent away from their tasks is directly proportional to the amount of time they need to resume work.
Game Developer Magazine analyzed 10,000 programming sessions recorded from 86 programmers using Eclipse and Visual Studio, and surveyed 414 programmers, and discovered that a programmer needs up to 15 minutes to start editing code again following an interruption. When interrupted during an edit of a method, the person resumed work in under a minute only a modest 10 percent of the time, Parnin pointed out. Plus, there’s only one uninterrupted two-hour session per day in which a programmer can work in silence.
They also found out that the worst time to be interrupted is when you have the highest memory load. The silver lining of being interrupted comes into play when the person can either suspend their working state or reach a “good breakpoint” —this way the impact can be reduced. However, transitioning from a high memory state to a low memory state takes about seven minutes, so the interruption is (almost) never without consequences.
Planned interruptions vs unplanned interruptions
If you think an unplanned interruption is bad, how about a planned one? If you know you have a meeting later today, your whole day is ruined because you unwillingly tailor it to make sure you finish your tasks on time.
Paul Graham, computer scientist and venture capitalist described the difference between the maker’s schedule and the manager’s schedule and pointed out how meetings (a.k.a planned interruptions) can “blow a whole afternoon.”
When you’re operating on the maker’s schedule, meetings are a disaster. A single meeting can blow a whole afternoon, by breaking it into two pieces each too small to do anything hard in. Plus you have to remember to go to the meeting. That’s no problem for someone on the manager’s schedule. There’s always something coming on the next hour; the only question is what. But when someone on the maker’s schedule has a meeting, they have to think about it.
I find one meeting can sometimes affect a whole day. A meeting commonly blows at least half a day, by breaking up a morning or afternoon. But in addition there’s sometimes a cascading effect. If I know the afternoon is going to be broken up, I’m slightly less likely to start something ambitious in the morning. I know this may sound oversensitive, but if you’re a maker, think of your own case. Don’t your spirits rise at the thought of having an entire day free to work, with no appointments at all? Well, that means your spirits are correspondingly depressed when you don’t. And ambitious projects are by definition close to the limits of your capacity. A small decrease in morale is enough to kill them off.
Working late at night might sound like a good idea because there are no (or at least less) interruptions but, as Swizec Teller points out, even programmers need to sleep if they want to avoid burnout. So…what now?