Background: Health literacy is considered to be an important predictor of health status. The Cochrane Collaboration uses different forms of presenting summary information from systematic reviews to different audiences, including press releases, scientific abstracts, plain-language summaries (PLS) and Cochrane Clinical Answers (CCA).
Objectives: We compared the readability of different formats of Cochrane systematic-review summaries and of PLS written in different languages.
Methods: We retrieved all 164 press releases on Cochrane systematic reviews published by January 2016 and corresponding scientific abstracts, CCA and PLS in English, French, German and Croatian. SMOG index and characteristics of the text were measured using an online program https://readable.io/; SMOG index for Croatian was calculated using an adapted formula.
Results: CCA was the shortest and scientific abstracts the longest format for presenting summary information from Cochrane systematic reviews (Table 1). Press releases had the longest sentences compared to all other formats (Table 1). All formats had a high SMOG index, meaning that all formats required more than 14 years of education to be easily understandable. The SMOG index for PLS was significantly lower than for other formats (Table 1). German PLS translations had significantly more sentences that other translations, and French PLS had the longest sentences (Table 1). The SMOG index for French PLS was significantly higher than for German and Croatian PLS, with Croatian PLS having the lowest SMOG index among all PLS (Table 1).
Conclusions: Summary information formats for Cochrane systematic reviews have low readability, including the formats directed to the lay public in different languages. A systematic approach to the content and format is needed to ensure that they are suitable for the target audiences. We are currently assessing the relevance of the tone and sentiment of different formats to better understand affective states, social tendencies, and language-style cues of Cochrane information materials.