Web not for all: a large scale study of web accessibility

The Web accessibility discipline strives for the study and improvement of front-end Web design towards people with disabilities. Best practices such as WCAG dictate how Web pages should be created accordingly. On top of WCAG, several evaluation procedures enable the measurement of the quality level of a Web page. We leverage these procedures in an automated evaluation of a nearly 30 million Web page collection provided by the Portuguese Web Archive. Our study shows that there is high variability regarding the accessibility level of Web pages, and that few pages reach high accessibility levels. The obtained results show that there is a correlation between accessibility and complexity (i.e., number of HTML elements) of a Web page. We have also verified the effect of the interpretation of evaluation warnings towards the perception of accessibility.