Ecophon and the Stress Research Institute in Stockholm conducted a unique study in a real-life office environment to examine how sound affects people in open plan offices.
The aim was to see how the ceiling’s properties affect workers’ health, productivity and the perceived disturbance.
And the result was clear - a better sound environment significantly improves work effectiveness:
- Up to 16% reduction in perceived disturbance in general
- Up to 25% reduction in disturbance at close range
- Up to 21% reduction in disturbance at long range
- Up to 11% reduction in cognitive stress
Reduction in cognitive stress refers to improved concentration capability, improved memory capability, better decision making and easier to think clear. The figures above are based on comparison from the average results.
A unique set-up
The design of the study is unique in its kind due to the fact that:
- The study is a field study carried out in real-life conditions, whereas most other studies of sound environments are carried out in controlled conditions. A field study can produce significantly more credible results since psychological factors are taken into account.*
- The study is based on a cross over design that involved two different control groups. The same results were observed within both control groups.
The three phases of the study
The study was divided into three phases:
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1. Preparations of the sound environmentOn the weekend prior to the study, the sound environments on the two floors were changed without the workers’ knowledge:
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2. Switching better to worse and vice versaAfter three weeks, the sound conditions were switched between the floors during the weekend when no employees were present.
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3. Switching the acoustics back againAfter three weeks, we switched back again, which meant that:
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Improved distance of comfort
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The acoustics in the work environment were measured several times throughout the study, following the guidelines in ISO 3382-3. In this way, the employees’ comfort distance was measured.
The study showed that people are strongly affected by the sound environment in open plan offices. In terms of comfort distance, there was a clear difference in terms of speech spread:
The comfort distance was improved by 35% on the floor with better acoustics.
Perceived disturbance in generalThe improved sound conditions also resulted in significant findings of reduction in perceived disturbance in general. The same pattern was observed on both floors. The central bar (T2) shows the improved and the worsened sound conditions. |
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Test periods |
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Perceived disturbance at close rangeThe study showed significant findings of reduction in disturbance at close range with the improved sound environment. The same pattern was observed on both floors, although to different degrees. The central bar (T2) shows the improved and the worsened sound conditions.
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Level of disturbance ![]() |
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Perceived disturbance at long rangeThere was a significant reduction in disturbance at long range with the improved sound conditions. The central bar (T2) shows the improved and the worsened sound conditions.
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Level of disturbance ![]() |
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Perceived cognitive stressThe study also showed that the improved sound conditions lead to a significant reduction of cognitive stress. The central bar (T2) shows the improved and the worsened sound conditions.
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Level of disturbance ![]() |
Test periods |
Read the full reportThe study was conducted in collaboration with the Stress Research Institute in Stockholm under the leadership of Aram Seddigh, PhD, in Sundbyberg City Hall in the spring 2014. The study results were published in the Journal of Environmental Psychology in September 2015. |
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The Stress Research Institute is a national knowledge center focusing on stress reactions, sleep and health. The Institute is part of the Faculty of Social Sciences at Stockholm University.
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*Dr Nigel Oseland is one of the world’s leading workplace consultants. His studies of psycoacoustics shows that psychological factors have a greater effect than the sound itself.
For this reason, sound environments and the effects of changes made in a room must be studied in real office environments.
Otherwise the study risks missing the factors that have the strongest effect.