The US Courts pre-sentencing officers must calculate a recommended sentence that is used as a sentencing guideline by the trial judge. These calculations are complex and based both on policy as provided by the US Sentencing Guidelines as well as the best judgment and understanding of the pre-sentencing officer. Multiple alternative scenarios are usually calculated, with the most appropriate one used for the final "offense level" calculation.
I was responsible for redesigning the existing calculator. A key requirement was utilizing a newer front-end technology that would eliminate reliance upon an older and soon-to-be incompatible Java-based UI framework. My recommendation was to use Angular, which I quickly learned in tandem with the team's developers. I developed all the UI view and style code.
I designed the entire application based on both the existing application and an in-depth examination of the actual calculation processes as explained by a number of pre-sentencing officers. The growing use of tablets by federal judges mean that the new design would have to work well in that form factor, although use on any smaller screen was ruled out by management.
The most innovative aspect was designing a way to allow users to essentially step-through all the various possibilities inherent in the federal sentencing guidelines, while also allowing calculations to swiftly be changed in order to experiment with different results. I created a node-based pattern of hierarchical checkboxes and radio buttons to control this, with a complex behavior that allowed logical parent-child interactions.