Abstract:The authors investigated the occupants' perceptions of 47 commercial and institutional buildings worldwide. These investigations involved the personal distribution and collection of a questionnaire survey seeking the occupants' perceptions (scored on a 7-point scale) of some 45 factors: Operational; Environmental (including temperature, air quality, lighting, and noise); Personal Control; and Satisfaction (including design, needs, comfort overall, productivity, and health). Occupants were also invited to comment on nine of these factors. While it has been suggested that in the ideal situation the occupants would have no complaints about their indoor environment, the aim here was to discover the real situation-in particular the proportion of occupants who were prepared to make a comment, the general nature of the comments (positive, negative, or balanced), and whether these correlated with the occupants' perception scores. On average, 34 per cent of respondents took up the invitation to make a comment. As anticipated, the greater the number of positive comments, the better the perception score, and vice-versa. However, it appears that it only required around 20% of the comments to be positive for the perception score to exceed the mid-point of the seven-point scale, whereas 65% or more of negative comments were needed to go under that point. This paper details the nature of the correlation between the occupants' comments and the corresponding scores for a range of building operational and indoor environmental factors and speculates on their potential for the analysis and prediction of building performance from the perspective of the occupants.