Evaluating lighting satisfaction in a public library: A study on the reliability and validity of a lighting evaluation questionnaire

BackgroundProper workplace lighting enhances efficiency, productivity, and safety. However, quantitative measurements alone may not reflect lighting quality or user satisfaction completely. Utilizing reliable questionnaires and gathering users' feedback provides a more comprehensive evaluation of lighting conditions.ObjectiveThis study aimed to validate a lighting evaluation questionnaire and employed it to assess lighting conditions and user satisfaction within a public library environment.MethodsThis cross-sectional study, conducted in 2024 at a public library, combined quantitative data from a light meter with qualitative insights from 60 participants via a questionnaire. Lighting optimization was modeled using DIALux software. Questionnaire reliability was assessed through Cronbach's alpha and test-retest methods, while validity was evaluated using CVR and CVI. Relationships between lighting intensity and responses were analyzed using Spearman's rank and Mann-Whitney U tests.ResultsReliability analysis showed alpha values ranging from 0.847 to 0.978, while validity was confirmed with CVI and CVR values within acceptable ranges. Illuminance levels averaged 205, 87, and 407 lux for the site, and 305, 66, and 545 lux for the study hall. Approximately 74% and 94% of measurement points were below minimum and recommended standards. About 80% and 88% of respondents rated their perception of lighting in the site and study hall as average or lower, with 80% and 56% reporting average or low satisfaction. DIALux suggested LEDIUM fixtures to achieve over 500 lux.ConclusionsThis questionnaire is a valuable tool for assessing the quality of lighting. It can be utilized for designing, measuring, and preventing lighting dissatisfaction.