Establishing Consensus on Standardized Survey Measures of Time Outdoors in Nature

Abstract

Spending time outdoors in nature is linked to numerous health benefits. Still, there is little guidance on measuring time outdoors in nature, limiting measurement precision and cross-study comparisons. We used a modified Delphi process to identify essential concepts for survey-based measures of time outdoors in nature. Ninety-three experts from 25 countries participated from May to December 2024. At least 60% of experts agreed including four essential concepts in all surveys: duration, frequency, a specified recall window, and clarification that time must be spent "in nature" rather than merely outdoors. Another 26 concepts were identified as important for some studies, depending on the study context. Among these, experts believed that the type of natural setting, biodiversity, environmental factors such as air or noise pollution and heat, and validating self-reported data with objective data will be increasingly important to measure in the future. We conclude with survey batteries and hypotheses to test in future nature-health research.

Keywords: nature contact, green space, blue space, exposure assessment, questionnaire development, survey measures, environmental psychology, health and wellbeing, Delphi study, outdoor recreation, park visitation