Exploratory Factor Analysis of the eHealth Literacy Scale
As the current study used only 6 of the 8 original eHEALS items, we conducted an exploratory factor analysis on these items. Principal components analysis produced a single-factor solution (eigenvalue = 3.551, 59% of the variance explained). Factor loadings ranged from .62 to .84 among the 6 items. Internal consistency reliability was analyzed on the 6 items, producing a coefficient alpha of .86, where item–scale correlations ranged from r
= .50 to .73. These results are quite similar to those of Norman and Skinner [27
], where the single-factor solution explained 56% of the variance, the internal consistency reliability was alpha = .88, and the item–scale correlations ranged from r
= .51 to .76.
Confirmatory Factor Analysis of the Research Scales
We calculated 2-model fit analyses to insure the assumption that each scale is independent of the other scales. In the first set of analyses, we used confirmatory factor analysis to test the structure of 4 scales: eHealth literacy, outcomes perception, digital literacy, and Internet access.
The results confirmed that the 4 scales are independent of each other, and the 6-item scale used from Norman and Skinner’s [27
] eHEALS is considered an independent scale.
In the second set of confirmatory factor analyses we tested the independence of an additional 5 scales in our study: health information sources, health information content, motivations for information search, search strategy, and evaluation criteria. The results confirmed that the 5 scales are considered independent of each other (see Multimedia Appendix 2
Sociodemographic Characteristics of the eHealth Literacy Groups
We examined the characteristics of the high and low eHealth literacy groups focusing first on the demographic variables of gender, age, and socioeconomic status. The high and low eHealth literacy groups did not differ in gender. There were 321 (50.7%) and 325 women (49.8%) in the high (n = 633) and low groups (n = 653), respectively (χ2
1 = 0.11, P > .05). Likewise, the eHealth literacy score of men (mean 3.35, SD 0.89) and women (mean 3.31, SD 0.88) did not differ significantly (F
1,1284 = 0.94, P = .332). However, the high eHealth literacy group was significantly younger (F
1,1284 = 35.56, P < .000; mean 38.87, SD 14.40, years) than the low eHealth literacy group (mean 44.12, SD 17.00, years). The socioeconomic status of the high eHealth literacy group was also significantly higher than that of the low eHealth literacy group, as measured by education (mean score, on a 7-point scale, 3.99, SD 1.32 and mean 3.82, SD 1.33, for the high and low eHealth literacy groups, respectively, F
1,1274 = 5.43, P < .02). There were 264 (41.9%) and 228 (35.2%) respondents with academic degrees, respectively, in the high (n = 630) and low (n = 647) eHealth literacy groups.
The health status of the eHealth groups was significantly different between the eHealth literacy groups. Respondents who reported that they were chronically ill had a significantly lower eHealth literacy score (F
1,1270 = 8.87, P < .003; mean 3.19, SD 0.95) than respondents with no reported chronic illnesses (mean 3.37, SD 0.85). In addition, 164 respondents (25.3%) in the lower eHealth literacy group (n = 648) reported having a chronic illness, as compared with only 117 (18.8%) respondents in the higher eHealth literacy group (n = 624). The health status difference on eHealth literacy was independent of age: an analysis of variance on eHealth literacy revealed an insignificant interaction effect of health status and age (F
3,1262 = 0.695, P =.44).
Health status was also examined in terms of perceived health. There was no significant difference between the high and low eHealth literacy groups in perceived health (F
1,1276 = 0.432, P =.511). The high and low eHealth literacy groups reported similar self-rated health (mean 3.25, SD 0. 74 and mean 3.22, SD 0.68, for the high and low eHealth literacy groups, respectively).
Internet Access and Digital Literacy
eHealth literacy emerged as related to digital access and literacy. Respondents in the high eHealth literacy group had significantly more access to computers and used the Internet more frequently than did the low eHealth literacy group (F
1,1281 = 26.47, P < .001): the mean Internet accessibility score of the high eHealth literacy group was 6.19, as compared with a score of 5.86 among the low eHealth literacy group. Furthermore, the digital literacy reported by the high eHealth literacy group was significantly higher than that reported by the low eHealth literacy group: 2.67 and 2.24, for the high and low eHealth literacy groups, respectively (F
1,1280 = 88.34, P < .001).
Information Consumption: Health Information Sources, Health Information Content on the Internet, Health Website Evaluation Criteria
eHealth literacy is a marker for consuming more information, as displayed in . Overall, respondents in the high eHealth literacy group used significantly more information sources (F
1,1280 = 11.01, P < .001) than did the low eHealth literacy group. Looking at individual items in , there is a significant difference between the two groups in their use of written material such as books, newspapers, magazines, and the Internet; there is no statistically significant difference between the two eHealth literacy groups in their use of live information from radio and television, a pharmacist, a nurse, or a physician (all P > .05).
Scores for low and high eHealth literacy groups’ consumption of information on the Internet
Respondents in the high eHealth literacy group searched for significantly more content on the Internet (F
1,1280 = 66.28, P < .001) than did the low eHealth literacy group, irrespective of the type of health content: social (eg, social support groups), service-related (eg, availability of services, or information on physicians, hospitals, and pharmacies), and therapy-related content (eg, health status, procedures, and medication).
The use of the Internet was different in terms of the search strategies employed by each of the two eHealth literacy groups. As can be seen in , those high in eHealth literacy used every strategy significantly more often than those low in eHealth literacy (F
1,1280 = 87.08, P < .000). For example, they followed links, asked questions on Internet forums, followed recommendations of their friends and physicians, and used their Favorites list significantly more often than those low in eHealth literacy.
In addition, the use of the Internet by participants who scored high on the eHealth literacy scale was marked by significantly more scrutiny, caution, and evaluation of the information they retrieve (F
1,1280 = 52.21, P < .000). Thus, for example, they looked for a contact address, wondered about the reliability of the source and the accuracy of information, and formed an opinion about the accessibility and availability of the information on the particular site they encountered. Information evaluation is related to eHealth literacy (r = .26, P < .000), but as the size of the correlation indicates, it is not synonymous with eHealth literacy.
Outcomes of Information Search
Finally, those highly eHealth literate gained significantly more from their information search than did the low eHealth literacy group (3.40 and 2.76, for high and low eHealth literacy groups, respectively; F
1,1280 = 177.76, P < .001). The results are displayed in . Cognitively, people in the high eHealth literacy group reported gaining a better understanding of their health status, symptoms, and optional treatments (see items in ). They also benefited more instrumentally: the information search improved their ability to self-manage their health care needs, affected their health behaviors, and allowed them a better use of their health insurance. The benefits extended also to their interaction with the treating physician: they asked the physician significantly more questions than they would have without the digital information search, presented the physician with the information they retrieved, and felt significantly better positioned vis-à-vis the physician than did the low eHealth literacy group.
Scores for low and high eHealth literacy groups in outcomes of information search