Investigation of different subjective response scales for thermal comfort analysis: Likert-type and visual analogue scales

Within the framework of a study investigating interactions among indoor environmental factors, two experiments were conducted on the effects of visual stimuli on thermal perception. Thermal responses were recorded with two methods, one quantitative via physiological measurements and a subjective one using a questionnaire. The questionnaire was developed on the basis of the standard EN ISO 10551 (2001-06-01) and recent publications on thermal comfort [1]–[3]. Two types of measurement scales were used, i.e., Likert-type and visual analogue. The first type was used for the questions about the thermal sensation, thermal comfort and thermal preference of the subjects and for the thermal sensation of their body parts (hands, feet and body). The only visual analogue scale in the questionnaire referred to the acceptability of the local climate in the room where the experiment was conducted. Different outcomes were recorded for the survey questions as they assess different aspects of thermal perception, confirming the outcome of previous studies [4], [5]. The comparison between Likert- and visual-analogue scales shows a much broader variety of responses for the visual analog scale. We assume that this is due to the nature of the measurement technique that allowed fine-tuned judgement of the indoor climate on a scale from 0 (acceptable) to 100 (unacceptable). The Likert-type scales of the other questions, on the other hand, gave the chance to choose only among five or seven fixed answers, leading to responses much more restricted around particular values. As an outcome for the specific topic of our research (i.e., the study of interactions between visual and thermal factors), investigating in general small effect size, we argue that a measurement scale leading to a bigger variety of responses is more suitable. The development of a single value incorporating several responses from different questions is currently under discussion.

Presented at:
Perception of thermal comfort and pain - are we assessing their dynamics right?, Heidelberg, Germany, November 9-10, 2017

 Record created 2018-01-11, last modified 2019-03-17

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