The Effect of Survey Scale Sizes on How People Assess the Effect of the Built Environment on their Work Performance

Increase in employee work performance could lead to additional savings for businesses, and therefore investments to improve the indoor work environment could be very cost effective. However, these business decisions are based on self-reported work performance measures from surveys. Doubts have been raised as to the accuracy of these measures.

In addition to the uncertainties of the self-reported measures, two major post-occupancy surveys by Building Use Studies (BUS) and Occupant IEQ surveys by the Center for the Built Environment (CBE) use two different scales for occupants to report the change in their work performance. This research examines how the two scales influence people in how they report the environmental effect on their work performance.

An experiment has been conducted under three pink-noise conditions to obtain self-reported work performance measures using these two different scales for comparison. Other self-reported indicators of work performance such as motivation, job satisfaction, fatigue and distraction were also collected through surveys, and cognitive tests were conducted to obtain objective measures of work performance.

The results from this experiment show trends for the BUS scales that are 2–3 times larger than results from using CBE scales. These results are significant when the results are correlated with other self-reported indicators; however, the differences were not statistically significant when the scores were correlated with environmental conditions and cognitive performance. The data suggests that the two scales generate different results.

Different scales leading to different results suggests that use of these two surveys could lead business investment analysis in misleading directions. If the productivity bonus of an investment is 5% according to one and 10% according to the other, there is a problem. Business investment analysis using self-reported work performance as an estimate of actual work performance could be misleading if self-reported work performance is used to directly calculate hours of work and savings achieved. Further studies should recruit more subjects, consider other environmental stressors and examine differences obtained by using different survey questions.