I Don't Understand You but I Trust You: Using Computer-Aided Text Analysis to Examine Medical Terminology Use and Engagement of Vaccine Online Articles

A defining feature of online information, such as in the areas of vaccines, is the interaction it can stimulate between users and the content, as they react, share, and comment. Online health articles that engage audiences are more likely to promote behaviour change, since engagement has been found to be associated with deep learning and comprehension, and is a critical step in the persuasion process. Using online articles about vaccine as an example, the present study examined whether practitioners should reduce medical terminology to lower the readability level or increase medical terminology to engage more audiences.

Most people have to rely on certain characteristics of an online health article, such as language and terminology, to determine if it is credible. Nevertheless, based on public health departments' recommendations and guidelines, it can be predicted that health practitioners and message designers will focus more on reducing the use of medical terms and lowering the readability levels to make health information easier to understand.

Previous studies have found that, compared to pro-vaccine articles, a larger percentage of anti-vaccine articles can only be understood by college students or college graduates. A possible explanation is that anti-vaccine articles may use many medical terms to look professional and credible to their audience. This approach can be explained by the staged model of trust, which highlights the importance of heuristics in message design. When viewers find abundant medical terminology in anti-vaccine articles, they may be more likely to believe that these articles are written by experts and thus can be trusted. The presence of medical terminology may also contribute to people's sharing of vaccine articles. In this context, the present study also asked questions about differences between pro- and anti-vaccine articles in terms of their use of medical terminology, their readibility, and their engagement.

The study used computer-aided text analysis (CATA) to analyse 541 pro-vaccine articles and 382 anti-vaccine articles. SharedCount, an open source online programme, was used to collect an article's total number of the shares, reactions, and comments on Facebook, Google+, LinkedIn, Pinterest, and StumbleUpon. This number was regarded as an article's engagement in the present study. SMOG (Simple Measure Of Gobbledygook) was used to estimate health information reading levels.

 Results:

• Anti-vaccine articles included significantly more medical terms than did pro-vaccine articles.
• Neither pro- nor anti-vaccine articles' readability levels were significantly related to medical terminology.
• Both medical terminology and readability significantly predicted pro-vaccine articles' engagement, yet only medical terminology significantly predicted anti-vaccine articles' engagement.
• Using easy language significantly decreased engagement in pro-vaccine articles.
• The number of medical terms in pro-vaccine articles significantly decreased from 2007 to 2017 - on average, by 5% per year. The number of medical terms included in anti-vaccine articles did not significantly change from 2007 to 2017.
• Pro-vaccine articles' readability levels significantly decreased from 2007 to 2017, while anti-vaccine articles' readability levels did not significantly change in this time period.

The researcher notes that the findings that pro-vaccine message designers limited the use of medical terms and made vaccine articles easier and easier to understand over the years suggest they have been following Centers for Disease Control and Prevention (CDC) and National Institutes of Health (NIH) guidelines. However, simply reducing the use of medical jargon as recommended by CDC and NIH may not be a good strategy to engage more audience, as the results of this study illustrate.

Some guidelines for health message designers and practitioners:

• Instead of simply reducing the use of medical terminology to reduce readability levels when creating health education materials, use simple sentence structures. Complex sentence structures tend to require a high readability level, which may make it difficult for health information seekers to concentrate on reading and understanding the text.
• Increase the use of medical terminology to look professional and credible while providing hyperlinks, references, or notes to explain terminology for those who need them.

"Future studies are recommended to apply the methods and findings to other health issues, such as the coronavirus pandemic."