Collecting global health data is an imperfect science: Workers tramp through villages to knock on doors and ask questions, write the answers on paper forms, then input the data -- and from this messy, gappy information, countries and NGOs need to make huge decisions. Data geek Joel Selanikio talks through the sea change in collecting health data in the past decade -- starting with the PalmPilot and Hotmail, and now moving into the cloud.

The big-data revolution in health care

For decades, global health relied on paper forms and manual data entry, leaving critical questions about disease, medicine, and even child mortality largely unanswered. In many countries, knowing how many children have been vaccinated requires months or years of door-to-door surveys, with stacks of forms often never processed. By harnessing cloud technology and simple mobile phones, data collection now happens in real time, empowering health workers to make informed decisions instantly. This shift shrinks timelines from years to minutes, turning scattered guesses into actionable knowledge.