Reliability of an Item Set Assessing Indoor Climate in Offices—Results From Field Studies and Laboratory Research

Assessing building user needs and preferences is widespread and often questionnaire surveys are applied in order to assess environmental perception and satisfaction. A central question in this context is the quality of the questionnaires used, but little is known regarding their reliability. The present study addresses interdisciplinary aspects such as engineering and psychological sciences to answer the questions: Are the same item sets applicable in various settings (e.g., seasons)? Is there any difference in the reliability of item sets assessing user satisfaction in field vs. laboratory research? In the present study, reliability analyses of an item set regarding satisfaction with indoor climate including the ASHRAE thermal sensation scale (single-item) as well as the thermal preference question were conducted with respect to season, office type, age group, and sex. Field data were gathered via post occupancy evaluation from 46 office buildings in Germany. Additionally, comparable items from laboratory research were subjected to a reliability analysis. Results revealed predominantly good to excellent Cronbach\u27s alpha values for the field studies. The values from the laboratory study were lower, although comparable (acceptable), partly due to the differences in variation in responses in field vs. laboratory settings. Results showed that questionnaires assessing user\u27s satisfaction need to be set in relation with the given context for reliable interpretation. Further research could validate our results with larger samples for laboratory data. Interdisciplinary research is necessary in order to further develop methodological approaches in the field of user comfort research

Evaluating assumptions of scales for subjective assessment of thermal environments – Do laypersons perceive them the way, we researchers believe?

People's subjective response to any thermal environment is commonly investigated by using rating scales describing the degree of thermal sensation, comfort, and acceptability. Subsequent analyses of results collected in this way rely on the assumption that specific distances between verbal anchors placed on the scale exist and that relationships between verbal anchors from different dimensions that are assessed (e.g. thermal sensation and comfort) do not change. Another inherent assumption is that such scales are independent of the context in which they are used (climate zone, season, etc.). Despite their use worldwide, there is indication that contextual differences influence the way the scales are perceived and therefore question the reliability of the scales’ interpretation. To address this issue, a large international collaborative questionnaire study was conducted in 26 countries, using 21 different languages, which led to a dataset of 8225 questionnaires. Results, analysed by means of robust statistical techniques, revealed that only a subset of the responses are in accordance with the mentioned assumptions. Significant differences appeared between groups of participants in their perception of the scales, both in relation to distances of the anchors and relationships between scales. It was also found that respondents’ interpretations of scales changed with contextual factors, such as climate, season, and language. These findings highlight the need to carefully consider context-dependent factors in interpreting and reporting results from thermal comfort studies or post-occupancy evaluations, as well as to revisit the use of rating scales and the analysis methods used in thermal comfort studies to improve their reliability

The Scales Project, a cross-national dataset on the interpretation of thermal perception scales

Thermal discomfort is one of the main triggers for occupants' interactions with components of the built environment such as adjustments of thermostats and/or opening windows and strongly related to the energy use in buildings. Understanding causes for thermal (dis-)comfort is crucial for design and operation of any type of building. The assessment of human thermal perception through rating scales, for example in post-occupancy studies, has been applied for several decades; however, long-existing assumptions related to these rating scales had been questioned by several researchers. The aim of this study was to gain deeper knowledge on contextual influences on the interpretation of thermal perception scales and their verbal anchors by survey participants. A questionnaire was designed and consequently applied in 21 language versions. These surveys were conducted in 57 cities in 30 countries resulting in a dataset containing responses from 8225 participants. The database offers potential for further analysis in the areas of building design and operation, psycho-physical relationships between human perception and the built environment, and linguistic analyses

The Scales Project, a cross-national dataset on the interpretation of thermal perception scales

Thermal discomfort is one of the main triggers for occupants’ interactions with components of the built environment such as adjustments of thermostats and/or opening windows and strongly related to the energy use in buildings. Understanding causes for thermal (dis-)comfort is crucial for design and operation of any type of building. The assessment of human thermal perception through rating scales, for example in post-occupancy studies, has been applied for several decades; however, long-existing assumptions related to these rating scales had been questioned by several researchers. The aim of this study was to gain deeper knowledge on contextual influences on the interpretation of thermal perception scales and their verbal anchors by survey participants. A questionnaire was designed and consequently applied in 21 language versions. These surveys were conducted in 57 cities in 30 countries resulting in a dataset containing responses from 8225 participants. The database offers potential for further analysis in the areas of building design and operation, psycho-physical relationships between human perception and the built environment, and linguistic analyses

Cathy O'Brein, federal fisheries' consumer consultant, prepared one of her favorite fish dishes for a visiting consumer

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