Friday May 24 2013
Offices with more workers saw more sick days taken
Open plan offices make employees “less productive, less happy, and more likely to get sick” reports the Mail Online website.
The article is actually based on a number of studies, but the one we found most interesting was a national survey from 2011, conducted in Denmark, looking at self-reported sick days of open plan workers compared to individual office workers.
The study found that people working in an enclosed office space reported lower levels of sickness compared to those working in an open office.
Theories offered by the researchers as to why this may be the case, include:
- open plan offices expose people to more noise which could increase their stress levels, making them more vulnerable to illness
- the open plan design makes it easier for viruses to spread from one worker to another
Still, as the researchers themselves point out, this type of study cannot prove either theory.
A limitation of the study is that it relied on self-reporting. People were asked to remember and estimate the number of sick days they had over the past year. So participants could have consistently over or underestimated the time off they’d taken, depending on their circumstances.
If you do think that your place of work may be impacting on your health, visit the NHS Choices Workplace health section for advice on useful steps you can take.
Where did the story come from?
The study was carried out by researchers from Denmark and was funded by the Danish Ministry of Employment and the Danish Working Environment Research Fund.
The study was published in the peer-reviewed Scandinavian Journal of Work, Environment and Health.
The Mail Online’s reporting was generally accurate on the study in question. The website also discussed evidence from other studies looking at the impact of open plan offices on stress levels, productivity and health.
We cannot comment on the accuracy of the reporting of these others studies as we have not looked at them.
What kind of research was this?
This was a cross-sectional study aiming to find out whether shared and open plan offices are associated with more days off sick than cellular offices comprising one occupant.
A cross-sectional study is a good way of assessing a situation at one point in time, or asking people to recall their recent experiences. The main weakness of this study type is that it cannot establish cause and effect, for example, whether open plan offices cause people to be off sick more often or whether people who are generally of sick more often tend to work in open plan offices. The method also struggles when it involves asking people to recall events of interest from the past, which can be prone to error or bias – specifically recall bias.
It could be the case that people are more likely to recall being genuinely sick with the flu than when they decided to “pull a sickie” because they fancied a lie-in in bed.
What did the research involve?
The research involved a subset of the results from a national survey of Danish inhabitants between 18 and 59 years of age, consisting of 2,403 employees that reported working in offices.
Based on the survey results, office workers were divided into four categories according to type of office:
- cellular offices comprising one occupant
- shared offices comprising two occupants
- shared offices comprising three to six occupants
- open plan offices comprising more than six occupants
The different types of offices were characterised according to self-reported number of occupants in the space.
Sickness absence was assessed with the question “In total, how many sick days have you taken in the last year?”
The main comparison was self-reported sickness absence days depending on the type of office.
The analysis was adjusted for factors that could influence the rate of days off sick (confounders), which included:
- socioeconomic status
- body mass index (BMI)
- alcohol consumption
- smoking habits
- physical activity during leisure time
What were the basic results?
The average (mean) number of self-reported sick days in the last year by number of people in the office was as follows:
- one occupant: 4.9 days
- two occupants: 8.0 days
- three to six occupants: 7.1 days
- more than six occupants: 8.1 days
Compared to cellular offices containing one person, this meant:
- occupants in two person offices had 50% more days of sickness absence, (rate ratio (RR) 1.50, 95% confidence interval (95% CI) 1.13 to 1.98)
- occupants in three to six person offices had 36% more days of sickness absence, (RR 1.36, 95% CI 1.08 to 1.73)
- occupants in open plan offices (more than six people) had 62% more days of sickness absence (RR 1.62, 95% CI 1.30 to 2.02)
How did the researchers interpret the results?
The researchers’ concluding remarks are included below in full:
“Open plan offices have become popular because they are designed to facilitate communication and accommodate knowledge sharing. However, our study showed that occupants sharing an office had a significantly higher number of days of sickness absence than those in cellular offices. Consequently, employees, employers, and society in general pay a high price for the benefits of open plan offices in terms of sickness absence and loss of productivity.”
This survey-based research suggested people in open plan offices may experience more days of sickness than people who have their own office and don’t share. The results only show an association and do not prove cause and effect. Neither did the research investigate what might be causing this relationship, although it did speculate about this in its discussion of the results.
The study had some strengths, including that it managed to recruit a reasonable number of people, but it also had many drawbacks that limit the conclusions that can be drawn from it.
The main weaknesses of the study were picked up and acknowledged by the study authors themselves, but were not discussed in the media reporting. They include how both the type of office classification and sickness absence were based on self-reports. Self-reporting sickness absence during the last 12 months may be prone to error in recalling the detail accurately. It may also be a source of recall bias if one group systematically under or overestimate the number of sick leave days they had taken. This could lead to misleading results. However, the reporting of the number of occupants in the office space is not likely to be affected by memory or a source of bias.
The research only looked at sick days. The Mail Online’s reporting about people in open plan offices being “less productive and less happy” was drawn from other research. This could well be accurate, but was not reviewed here.
Nonetheless, in the discussion, the researchers of the Danish study pointed to five possible explanations for how open plan offices might lead to more sickness leave:
- higher noise exposure in the open plan office
- differences in the type of ventilation used
- people in shared and open plan offices are more likely to be exposed to viruses than occupants in cellular offices
- difference in psychosocial work environment, for example, lack of privacy in the open plan office causing problems and sickness
- open plan offices may reduce employees’ autonomy (discretion and freedom to work), leading to higher stress levels
Another possible explanation, not discussed by the researchers, could be cultural. If you work in a large office where your co-workers are frequently taking days off sick, then you may be more tempted to take time off yourself.
None of the above explanations were explored in the Danish study and all remain speculative.
A common reason that the open-plan office environment is popular with employers is they tend to be cheaper in terms of operating costs such as heating and lighting.
An arguably interesting avenue of research would be to see if the perceived economic benefits of an open-plan office were actually outweighed by the alleged disadvantages, such as increased levels of sickness and reduced productivity.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.