Productive plants

Potted Plants Boost Productivity

In a press release that has gone about as viral as anything from academia is likely to, a team of researchers from Britain, Netherlands and Australia are reported as finding that indoor plants boost office productivity by 15 per cent.  I quote from the Independent:

".....the researchers compared the environments of “lean” and “green” offices in the UK and The Netherlands. They looked at how the two types of surroundings impacted upon staff’s perceptions of air quality, concentration, and workplace satisfaction and monitored productivity levels over an 18-month period.  The research demonstrated that plants in the office significantly increased employee's satisfaction and improved their self-reported levels of concentration and perceptions of air quality."
All reports of the research put considerable emphasis on the fact that this conclusion is at odds with modern "lean" management techniques.  Some reports quote Professor Alex Haslam from UQ’s School of Psychology as saying:

“Office landscaping helps the workplace become a more enjoyable, comfortable and profitable place to be.....It appears that in part this is because a green office communicates to employees that their employer cares about them and their welfare.......Employees from previously lean office environments experienced increased levels of happiness, resulting in a more effective workplace.” 

The particular piece of research might be sound enough, and I will edit this post with my opinion when I have read the original paper (Edit: I have, now.  See below.). But in the meantime I would urge caution.  As an experienced colleague of mine immediately commented, "one two-month study looking at two offices" is not something he would extrapolate from. Contrary to the claims of the authors, the percentage improvement found in this study is not consistent with the rest of the literature, which tends to report lower gains of productivity, and very much a dependence on other contextual variables (Again, see the edit below).

My own difficulty is not so much questioning the validity of the findings.  Rather the notion that if plants in the office achieve 15% increase in productivity, that would suggest that almost all other available improvements in indoor environmental quality have little or no hope of being of anything but marginal value.  There is only so much increase in productivity that is achievable!  In other words no other green building initiatives would be justified on the basis of productivity gains.

I have a suspicion that reading the full paper, I will find the authors placing rather more emphasis on the so-called Hawthorne Effect, named after one of the early time and motion studies. That was where it was first accidentally, but elegantly demonstrated that the dominant cause of improved productivity was employees feeling like management cared. The comments by Prof Hallam as good as say so.

Nevertheless, as my colleague also commented, there is a very  strong evidence base originally from NASA research and much work since, for the IAQ benefits  from indoor plants. So not all the benefit is psychological (perception/cognition), there are physiological aspects as well.

Parenthetically, this also leads me to comment, once again, on the sloppy misinformation so common in reporting such work. It isn't the fault of the study authors that a contributor to the Guardian claims this work to be "the first to look at long-term impacts of plant life in offices".  But I am getting twisted and bitter.

BIG EDIT:

I have now had the opportunity to read the entire paper, courtesy of one of the prime authors (see comments below).

The most striking difference between the populist reports and the actual paper, is the absence of any simplistic headline quantification of the potential improvement in productivity. Second, the authors emphasise that their primary motivation is their disquiet about how poorly founded is the assumption that lean environments are more productive than enriched environments. In their own words:

"...the focus of this study was on the differences between lean space and green space. This is clearly a narrow band of potential environmental options. Nevertheless, this very narrowness can itself be taken as providing evidence of the relatively minimal changes that seem to be needed to deliver both psychological and commercial advantage. In this context, it is all the more remarkable how reluctant organizations often are to take advantage of such opportunities to improve the quality of work environments for employees."

 Thirdly, the emphasis of the paper is to try and move investigation of productivity out of the laboratory into the real world. This is a methodological issue that authors share with almost all other fields of endeavour investigating human beings.  So it is especially relevant that the paper recognises poor objective evidence of improvement in productivity in the first two of its three reported studies – to the point that the third study, while located in a real-world office, is in fact set up very much like a laboratory experiment. It is only as a consequence of that constrained experiment that they can finally point to improvement in efficiency without loss of quality in the work done in the enriched environment.

Fourth, constrained by its own space limitations, the actual paper contains a fairly comprehensive review of the literature that relates to greenery in office space. It certainly isn’t possible to accuse the authors of ignoring that history. So it is interesting to note that in the end they do not claim any particular links between productivity and pot plants specifically. In fact, while all the other possible benefits of greenery in an office space are actually confounding variables in this study, really, the pot plants are just the most convenient and unambiguous means of enriching the workplace.

If you have access to a university library subscription, read the original:
The relative benefits of green versus lean office space: Three field experiments.

Nieuwenhuis, Marlon; Knight, Craig; Postmes, Tom; Haslam, S. Alexander

Journal of Experimental Psychology: Applied  
Vol 20 Issue 3 pp. 199-214

This one is free:
A study of interior landscape plants for indoor air pollution abatement 
Wolverton, B. C.; Douglas, Willard L.; Bounds, Keit
NASA 1989