Disaster Health Literacy - development and validation of a short measurement instrument in German to supplement the HLS instruments.

Introduction: In many countries, promoting the ability to protect one's own life and health and to help oneself when faced with adversity is a cornerstone of disaster risk reduction. For this reason, the population must be able to access, understand, assess and apply the information necessary to do so. So far, there have been only a few attempts to define this so-called "Disaster Health Literacy" (DIS-HL), and there is a lack of easy-to-use instruments to measure it. The aim of this research was to develop such an instrument based on a conceptual framework and to report on its content and face validity.

Methods: As an interdisciplinary and interinstitutional working group we applied a standardized approach to the development of instruments for social science survey research. Based on a scoping review, we constructed a conceptual framework and defined an items list. We conducted an online expert review ( = 12) to test content validity and used cognitive interviews ( = 10) and real-life interviews ( = 10) to assess face validity. Item and scale context validity indices were calculated, and a formal and summative analysis of the qualitative data was carried out.

Results: Based on suggestions from the literature, we defined DIS-HL and identified key components of the construct. In item development, we considered four cognitive dimensions (access, understand, appraise, apply), the heterogeneous information requirements before, during and after events, and three information task domains (prevention, acute response, access to care). Based on the experts' feedback and the results of the face validity assessment we reduced the original 15 items to 12 items. Furthermore, we made moderate adjustments to the content and language of the items and shortened the introductory text to improve clarity and comprehensibility.

Discussion: Our research strongly supports the relevance and content validity of the short DIS-HL measurement instrument. However, further psychometric tests (factor analysis) are necessary to verify its quality. To support this, a large-scale pilot test will be conducted as part of the third national representative survey on health literacy in Germany (HLS-GER 3). If this test is successful, an English translation and international adaptation of this instrument could be considered.