How do you transform a traditional paper-based instrument that has been in use for 60+ years into a modern web -based application? Nielsen is using an iterative testing process to create such a web -based instrument that could eventually replace paper. Nielsen conducted a series of tests using a probability based address sample to recruit the general population, aged 13 and older, to complete a one week web -based diary of their radio listening. The first web application, or eDiary, pilot test was conducted in 2011. The results of the test identified potential usability issues with the online application such as overlapping time entries and conflicting time issues. Following the field test, a usability study of the online diary application was conducted. Web savvy and non-web savvy participants were invited to use the application and provide feedback on the user experience. The focus of the usability study included content and features of the online diary such as radio buttons, checkboxes, and a slider bar. In winter 2012, an in- home ethnography study was conducted in three markets where participants used scenarios and completed tasks to enter radio listening entries in a diary page. Additionally, expert reviewers were commissioned to review the usability of the overall website from registration to completion of diary keeping. The results from the three studies were consistent and resulted in a re-design of the eDiary application. We will present the results from the eDiary usability study as well as the comparison of the results from the pilot tests. We will show the features of the online diary and the effect usability testing had on data quality such as time precision and duplicate entries. The results show that a simple approach is usually the optimal one.