Every open office has a number most people have never heard of: its distraction radius. It is the distance at which a normal conversation stops being understandable, and there is an international standard for measuring it. In a well-designed floor it is under 5 meters. In a bad one it is over 10, which means a single phone call can pull focus from nearly every desk in the room.
Here is the science behind it, the numbers that matter, and what actually shrinks it.
The study that changed the open-office debate
In 2018, Harvard researchers Ethan Bernstein and Stephen Turban tracked employees at two Fortune 500 headquarters before and after each moved to an open plan. Instead of surveys, they used wearable sensors and message logs. The result: face-to-face interaction dropped by roughly 70%, while email went up 56% and instant messaging went up 67%. (Philosophical Transactions of the Royal Society B, 2018)
The walls came down, and people put on headphones and started typing to each other instead. That is not a failure of open space. It is a failure of acoustics.
It’s not the volume. It’s the words.
Acousticians measure how understandable speech is with the Speech Transmission Index (STI), a scale from 0 (pure noise) to 1 (perfectly clear). The key finding from Finland’s Institute of Occupational Health: work performance starts to drop once STI passes about 0.20, and the damage is basically maxed out by 0.60. Across lab studies, performance losses from overheard speech ranged from 4% to 45% depending on the task. (Hongisto, Indoor Air, 2005)
That is why a humming HVAC system barely registers but a coworker’s half of a phone call wrecks your concentration. Your brain cannot ignore words it can understand.
The distraction radius, defined
The international standard for open-office acoustics, ISO 3382-3, turns this into distances you can measure on your own floor:
- Distraction distance (rD): where STI falls below 0.50. Good target: 5 m or less. Poor: more than 10 m.
- Privacy distance (rP): where STI falls below 0.20, the point where speech stops being understood at all.
- Spatial decay (D2,S): how many decibels speech loses each time the distance doubles. Good target: 7 dB or more.
- Speech level at 4 m: good target is 48 dB(A) or less.
Put simply: if your distraction distance is 10 meters, every desk inside a circle 20 meters across hears every conversation clearly enough to lose focus. (ISO 3382-3 overview, Odeon)
What each distraction actually costs
UC Irvine’s Gloria Mark shadowed office workers with a stopwatch and found it takes an average of 23 minutes and 15 seconds to get back to the original task after an interruption, usually with two other tasks in between. Multiply that by the number of calls happening inside your distraction radius on a busy Tuesday.
The quiet paradox: a little background noise helps
This is the counterintuitive part. Canada’s National Research Council found people prefer background sound around 45 dB(A) when speech is coming from the next workstation, and it should not exceed 48 dB(A). A dead-silent office makes every word carry. Acceptable speech privacy requires getting speech intelligibility down to about 0.20. (Bradley & Gover, NRC, 2004)
What actually shrinks the radius
The research is consistent: no single fix does it. It takes a combination.
- Sound-absorbing ceilings. NRC modeling found ceiling absorption and screen height have the largest effect on speech privacy between workstations.
- Taller, absorptive screens. Low panels barely block seated speech. Height and sound-absorbing surfaces both matter.
- Layout. Point people who talk all day (sales, support) away from people who need focus, and put circulation paths and storage between them.
- Enclosed rooms for the loud stuff. The acoustics literature explicitly recommends adding small closed spaces for calls and focused work. That is exactly what phone booths and privacy pods do: they take the most distracting source, a phone call, and remove it from the open floor entirely.
Measure before you buy
You do not need to guess. A walkthrough can map who talks, who focuses, where the calls happen, and which existing panels can be raised, re-skinned, or rearranged before anything new is purchased. In most Denver offices, some of the fix is already in the building.
MORE, Inc. reconfigures Denver offices for how people actually work: panel height changes, layout rework, phone booths, and huddle rooms. Call 303.371.4049 or visit moredenver.com to schedule a walkthrough.
FAQ
What is a good distraction distance for an open office?
Under ISO 3382-3, a distraction distance of 5 meters or less indicates good acoustic conditions. Above 10 meters is poor, meaning speech stays distracting across most of the floor.
Does adding background noise really help?
Yes, within limits. Research from Canada’s National Research Council found about 45 dB(A) of background sound is preferred when speech comes from a nearby desk, and it should stay under 48 dB(A). Too quiet, and every word carries.
How much does overheard speech hurt productivity?
Lab studies summarized by Finland’s Institute of Occupational Health show performance losses of 4% to 45% depending on the task, with losses starting once speech becomes partly intelligible (STI above about 0.20).
Do phone booths actually fix open-office noise?
They fix the worst source. Phone calls are highly intelligible one-sided speech, the most distracting kind. Moving them into an enclosed booth removes them from the open floor, and the acoustics literature specifically recommends small enclosed spaces for calls and focused work.