Assessing the impact of the indoor environment on productivity : A case study in a university building in Stockholm

Abstract: The impact that the indoor environment has on productivity is a topic that has been investigated in numerous studies. There are a variety of different methods that have been used to evaluate productivity with. There are quantitative methods and there are qualitative ones, and both have been used in the literature as indicators or real productivity. The quantitative ones are for instance short arithmetical or linguistic performance tests or measurements of the actual quantitative output of a job. Qualitative assessments of productivity consist of different ways of allowing the subjects to rate their own productivity. Both these two approaches of evaluating productivity are claimed to be subject to different issues, and the question of which way is preferable is a matter of contention among the researchers. The quantitative approach is claimed to be unable to reflect the complex and qualitative output of many modern jobs, while the qualitative one is believed to be highly influenced by bias. This master’s degree project has investigated the associations between the two approaches and conducted a qualitative assessment of the impact of the indoor environment on the productivity in a university building in Stockholm. Numerous studies have been reviewed that include both quantitative evaluations of productivity and qualitative evaluations of the indoor environment. Qualitative evaluations are for instance evaluations of environmental satisfaction, as well as evaluations of healthiness and productivity. The relationship between the quantitative measurements and the subjective evaluation is indeed complex. However, there appears to be a consistency to some extent between the two, and the trend seems to indicate that occupants who are more productive are also more satisfied with the indoor environment or perceive themselves to be healthier or more productive. A working hypothesis has been formulated; that subjective evaluations of the indoor environment may act as indicators of productivity. This approach has been used in a university building in Stockholm, where the productivity of the students has been evaluated through a survey, together with physical measurements of the indoor environment. The survey is designed based on the current literature within the field. It has a large emphasis on productivity, with several questions concerning it directly and indirectly. The physical parameters that were measured were radiant temperature, air velocity, relative humidity, CO2- concentration and sound pressure level. Considerable correlations were observed between perceived productivity and environmental satisfaction, perceived environmental control and between different ways of evaluating productivity subjectively. The correlations between the physical measurements and the subjective evaluations were in general considerably weaker than the ones between the different subjective parameters. The correlations between the mean CO2-concentration and productivity was weak, and similar findings were obtained concerning sound pressure level. This emphasise the importance of heeding the opinions of the occupants while evaluating the performance of a building, as physical measurements alone appear to be unable to reflect the users’ perspective reliably. The correlation between the thermal parameters (evaluated by the PMV- value) and the subjective evaluations were, on the other hand, considerably stronger. This may indicate that the thermal parameters are among the most influential ones in creating a productive workplace. Furthermore, the study discusses different methods that have been used to evaluate productivity with. It discusses their weaknesses and strengths and what elements they contain that may be used for future studies of productivity.