Spelling errors and 'shouting' capitalization lead to additive penalties to trustworthiness of online health information: Randomized experiments with laypersons.

Abstract

BACKGROUND. The written format and literacy competence of screen-based texts can interfere with the perceived trustworthiness of health information in online forums, independent of the semantic content. Unlike in professional content, the format in unmoderated forums can regularly hint at 'incivility', perceived as deliberate rudeness or casual disregard towards the reader, e.g. through spelling errors and unnecessary emphatic capitalization of whole words (online 'shouting'). OBJECTIVE. To quantify the comparative effects of spelling errors and inappropriate capitalization on ratings of trustworthiness independently of lay insight, and to determine whether these changes act either synergistically or additively on the ratings. METHODS. In online experiments, 301 UK-recruited participants rated thirty-six randomised stimulus paragraphs in the format of information from an unmoderated health forum (about multiple sclerosis) for trustworthiness using a semantic differential slider. Nine control paragraphs were compared to error-containing paragraphs including 5 instances of misspelling, 5 instances of inappropriate capitalization (‘shouting’), or a combination of the two. Data were analysed in a Linear Mixed Effects model. RESULTS. The mean trustworthiness ratings of the control paragraphs ranged from 32.59 to 62.31 (rating scale 0-100). Compared to the control paragraphs, paragraphs containing only misspellings were rated as being 8.86 points less trustworthy, inappropriate capitalization was 6.41 less, and the combination of misspelling and capitalization was 14.33 less. Misspelling and inappropriate capitalization show an additive effect (P < .05 for all). CONCLUSIONS. Distinct indicators of incivility independently and additively penalize perceived trustworthiness of online text independently of lay insight, eliciting a medium effect size.