This presentation made by Denice Ross at the Gov 2.0 Expo in 2010 describes the user–centered, evidenced-based approach to application design taken by The Data Center. Using the example of their repopulation mapping application, she explains how to delineate a clear task, identify an appropriate data set, post metadata in plain sight and in plain English, and conduct user field–testing. The presentation concludes with stories of actual users of the app, the decisions they needed to make, and how the data available in the app supported those decisions.