The use of visual aesthetics has been found to contribute to feelings of a positive Web experience. Accordingly, studies report strong correlations between aesthetics and facets of user experience like usability and credibility, but does this hold for accessibility also? Some believe that Web aesthetics impedes accessibility, while most Web designers perceive that the accessibility initiative is restrictive design-wise. These misconceptions have slowed down the advancement of an inclusive Web. Firstly, it is clear that the relationship between Web aesthetics and accessibility is still poorly understood. Secondly, tools capable of analysing the aesthetic quality of Web pages and relaying associated accessibility status information are lacking. This thesis addresses these two problems. In order to investigate this relationship, the aesthetic judgements of 180 users were elicited to help classify Web pages based on their visual quality using Lavie and Tractinsky's framework. The classified Web pages were then technically and manually audited for accessibility compliance using 4 automated tools, and 11 experts who used a heuristic evaluation technique known as the Barrier Walkthrough (BW) method to check for barriers which could affect people with visual impairments. Our results consistently showed that Web pages judged on Lavie and Tractinsky's classical aesthetic dimension as being `clean' had significant correlations with accessibility, suggesting `cleanness' to be a suitable proxy measure for accessibility. Expressive dimensions showed no such correlations. This insight was used to develop the EIVAA tool aimed at predicting the aesthetic quality of Web pages and using the information to provide accessibility ratings for the pages. Quantitative evaluations show that the tool is able to predict aesthetic quality in a way that mimics gold standards, especially along the design dimension `clean' where we observed tool-human correlations as strong as 0.703, thus making the associated accessibility predictions also acceptable. We envision that our findings will give the Web community a more holistic understanding of the interactions between the use of aesthetics and accessibility, and that our tool would inform Web developers of the implications of their designs.

More and more people choose to shop online in favor of physical stores. E-commerce websites are facing several challenges today including conversion rates and customers leaving the online shopping cart without making any purchases.  This thesis looks closer into how the aesthetics of an e-commerce website can lead to purchases and fewer abandoned carts. The goal is to answer how web aesthetics can influence customers’ desire to complete a purchase.  To answer the research questions a literature review has been carried out together with an empirical study. For the empirical study, three different designs were created, with one adhering to design principles and other two were not. Then, we conducted interviews to collect participant’s opinions about three designs and influence of their purchase decision.  The result showed that the aesthetically pleasing design was most liked by the par- ticipants. When comparing the three designs, 92% of participants preferred to buy from the good-looking design.  Through our research, we conclude that website’s aesthetics plays a significant role besides pricing and supply, that leads a customer to not abandon the purchase. In conclusion, customers value web aesthetics as it does influences their decisions. It can be argued that dislike of website design poses a risk that they leave the website without making any purchases.