Consolidating Climate Anxiety Scales Using Rasch Modelling

Despite being an important mental health consequence of climate change, climate anxiety assessment has been fragmented. Reviews of measures of climate anxiety raise concerns about content and convergent validity. We aimed to select the best functioning items from current climate anxiety measures to develop a condensed scale using Rasch methodology. We used a mixed-method approach across three studies. First, we pooled items from six measures of climate anxiety and neighbouring phenomena and used Rasch modelling to retain items that followed model assumptions in general public (N = 305) and university student (N = 143) samples. We then surveyed (N = 31) and interviewed (N = 12) clinicians and researchers about the relevance of the selected items and suitability of the scale for their professional practice. Finally, we tested the structure and validity of the retained items (N = 341). Of the 129 initial pooled items, we retained 22 that representatively cover the full scope of climate anxiety experience according to the theoretical model of climate anxiety. These items followed Rasch model assumptions and were deemed relevant by the expert participants. The candidate items exhibited good convergent and discriminant validity but did not predict wellbeing outcomes over and above an existing measure of eco-anxiety. We conclude that while our scale provides a useful representative measure of different climate anxiety presentations, its lack of incremental validity means it does not justify its existence as a new scale, and existing scales should be further validated.