Development of a Validated Lay Checklist (Info Without Side Effects) for Assessing Health Information on Websites: Mixed Methods Study

Background: The internet has become a major source of health information; yet, the quality of health information on websites varies considerably. Users’ ability to evaluate either the factual accuracy or the trustworthiness of health information on websites is limited, as around half of the European people have limited health literacy. Existing checklists and tools are either prepared for research purposes or to be used by health care professionals. They do not account for the lay user perspective, since they are too long and complicated to be used by laypersons, or were developed for printed health information only. Objective: The aim of the study was to develop and validate a checklist that enables laypersons to evaluate the trustworthiness of health information on websites without requiring prior training. Methods: We used a multistage mixed methods approach including (1) a comprehensive literature review to identify existing tools and quality criteria, (2) an expert Delphi study with 6 specialists in patient communication and health information, (3) 2 rounds of cognitive interviews with 19 lay users, (4) application testing on 15 selected web pages with information about health interventions with 20 additional lay users, (5) a determination of the factual correctness of 100 web pages with health information by assessing the difference between the claimed and factual strength of the evidence on these web pages, and (6) validation testing by research team members on these 100 web pages using a Bayesian logistic regression model to analyze the predictive validity. In the final step, we integrated all quantitative and qualitative results to select the final checklist items. Results: From an initial pool of 1740 items extracted from 73 documents, we systematically reduced the list through multiple evaluation and testing rounds. To ensure the checklist is user-friendly, we involved a diverse group of potential users. The final product, the Info Without Side Effects (iWISE) checklist, contains seven items that assess key aspects of health information trustworthiness, including the absence of advertising, balanced presentation of information, the limited use of professional jargon, origination from an independent organization, citation of sources, mention of scientific validation, and the presence of a publication date. The checklist demonstrated the ability to distinguish between evidence-based and nonevidence-based health information web pages in the German language: the validation testing showed that when all the items were marked with yes, there was a nearly 100% probability that the health information was also factually correct. Conclusions: The iWISE checklist represents a user-friendly, validated tool for evaluating the trustworthiness of health information about interventions on websites. With only 7 items, it is easy to remember and could significantly improve critical health literacy. Future research should test its reliability for social media posts and health information videos.