Predicting the health outcomes of important interventions

Population Services International

When we first came across the PSI DALY calculator, it was a clever tool in need of a redesign. Used primarily by PSI staff, the brilliance of the tool was far more present in its underlying mathematics than its presentation. As a powerful way to compare the impact of different types of health interventions in a large number of countries, the calculator allowed users to look for optimal mixes of products that would have the most beneficial outcomes for populations.

The old DALY calculator

Unfortunately, the original calculator did not orient users to its purpose or functionality, and it had an outdated design that made it unnecessarily hard to navigate. The calculator even had a logo that was no longer used by PSI. Even the name DALY calculator showed the preference toward an informed audience.

Our Redesign

Our new design started with a introductory page that matched the current look of the PSI brand and included a simple sentence letting users know what the tool was designed for. This was absent from the original calculator and made its purpose unclear to anyone unfamiliar with it before arriving.

In the previous version, the DALY calculator required people to go through a series of different pages for each step in the process, and to start from scratch if a single change was made. In the new Impact Calculator, we kept everything on one page and built separate tabs to allows users to easily add new country searches while saving their original data.


One of the key features we added to the new calculator was the addition of informational pages explaining the functionality of the underlying the formulas that power the calculator. Users can now see not only the calculations but a detailed explanation of how these formulas were derived.


By creating a tool with an improved visual and UX design, as well as important new features, were able to work with PSI to build a calculator that is less confusing, more enticing, and more powerful than the original. This new Impact Calculator will have the potential to reach a broader audience and should lead to even better analysis of what interventions provide the greatest health benefits for target populations.

Go to the Impact Calculator