Abstract-This paper discusses the design, development and evaluation of a data visualization prototype for a mobile application, for people with rheumatoid arthritis conditions. The visualizations concern ways of displaying graphically data for monitoring and evaluating the daily activities of rheumatoid arthritis sufferers. An initial visualization was developed and then a second was developed, aiming to be more usable and universally designed than the first version. An empirical experiment was used for evaluation and collection of quantitative data. Furthermore, semi-structured interviews were used for eliciting more qualitative data in terms of participant opinions. The overall results suggest that the second visualization was more usable and more universally designed than the first version. The paper concludes with some recommendations for future improvements.