Disparities between English and Spanish in readability of online endodontic information for laypeople

Background: In this study, the authors assessed the readability of online endodontic information in English and Spanish.

Methods: The authors performed a systematic search in Google in May 2016. Search queries were "root canal treatment" and "¿Qué es una endodoncia?" without limits or filters. The authors assessed English readability by using Flesch-Kincaid Reading Grade Level, Flesch Reading Ease Score, Gunning Fog Index, Coleman-Liau index, automated readability index, and Simple Measure of Gobbledygook (SMOG) index. The authors calculated readability for Spanish by using the Fernández-Huerta index and INFLESZ (Ines-Barrio).

Results: The authors assessed the first 100 consecutive sites identified with each search strategy and selected 117 sites. Readability scores for English-language sites were in the category of normal to read, easily understood by 13- through 15-year-old students (Flesch Reading Ease Score, 63, interquartile range (IQR) [53.9-66.2]; Gunning Fog Index, 10.4, IQR [8.8-12]; Coleman-Liau index, 12.5, IQR [11.6-13.3]; and automated readability index, 8.6, IQR [6.7-9.8]). SMOG results led to the estimation that only 7 years of education would be needed to understand these contents (SMOG, 7.6, IQR [6.5-8.8]). Spanish-language sites had a readability index normal for an adult, equivalent to a seventh or eighth school year (Fernandez-Huerta, 62.3, IQR [59.7-66.6]; INFLESZ, 57.5, IQR [55.1-62.1]). The authors found that 36.6% of English-language sites had some degree of difficulty for readers to understand their contents, whereas 23% of Spanish-language sites had some degree of difficulty (14.46; 95% confidence interval, -3.16 to 30.08).

Conclusions: Spanish- and English-language electronic health information about endodontic treatment is acceptable to read, but-particularly for English-language sites-there is an important proportion of sites scoring difficulty levels well above the recommendations.

Practical implications: The internet is a useful tool for communicating with patients, but available endodontic information is difficult for laypeople to understand. Endodontists should produce relevant materials in plain language to overcome this problem.