Paper	Individual Factors Affecting Online Health Information Information- Seeking Behavior	Methods of the Analysis	Limitations
[14]	Gender Age Educational level Economic status (household income)	French nationally representative surveys and health barometers	Selection bias cannot be excluded. Results are not generalizable to other countries (different from France). Data on trust in the information found are only available for the sample of health information seekers.
[15]	Gender Age Educational level Economic status (household income)	Cross-sectional study	Fewer details on the online health information-seeking behavior of Chinese internet users. Results are difficult to compare with those of previous studies. The study has been conducted before the COVID-19 epidemic in 2020, during which the degree and diversity of internet use has grown.
[16]	Gender Age Educational level	Turkish Statistical Institute (TSI) survey	Exclusion of several additional independent variables, such as health status, the presence of chronic diseases, health literacy, and eHealth literacy.
[17]	Health status	Questionnaire survey	The external validity is reduced because the study is skewed toward younger and more educated patients. Self-reported health status and chronic medical condition is used in the study.
[11]	Health status	Queensland Social Survey	Results are based on self-reported data. Under-sampling of adults aged younger than 35 years. The topic of health information sought and the timing and frequency of online information seeking are not assessed. It is a cross-sectional study but the direction of association cannot be determined.
[10]	Gender Age Digital technology literacy	Sets of analyses on the 2012–2014 US Program for the International Assessment of Adult Competencies (PIAAC) Data using Stata	The study does not consider the effect of young adults’ digital literacy skills, problem-solving skills, and numeracy skills on their health-seeking approach. Lack of the ability to claim causation.
[12]	Age	Analysis of 10 e-commerce sites	The study only examines successful e-commerce sites in Turkey.
[13]	Age	Workshop-based discussions with the target group of 20 young drug users	Results are not generalizable to other countries (different from Slovenia).
[9]	Gender	Representative national German health survey	The cross-sectional data used does not allow for causal attributions. Differentiation is made between people who are searching for information for themselves and those who are searching for others.
[8]	Education	Focus groups	The transferability of findings is limited to populations similar to participants in the study.
[18]	Health status	Health Information National Trends Survey 4 Cycle	Results are not generalizable to other countries (different from the USA).
[19]	Education	Health Information National Trends Survey	The study examined three time periods but it does not allow for a comparison of rates across years. In all survey research, findings are limited by recall bias.