  The widespread availability of cell phones has enabled non-profits to deliver
critical health information to their beneficiaries in a timely manner. This
paper describes our work to assist non-profits that employ automated messaging
programs to deliver timely preventive care information to beneficiaries (new
and expecting mothers) during pregnancy and after delivery. Unfortunately, a
key challenge in such information delivery programs is that a significant
fraction of beneficiaries drop out of the program. Yet, non-profits often have
limited health-worker resources (time) to place crucial service calls for live
interaction with beneficiaries to prevent such engagement drops. To assist
non-profits in optimizing this limited resource, we developed a Restless
Multi-Armed Bandits (RMABs) system. One key technical contribution in this
system is a novel clustering method of offline historical data to infer unknown
RMAB parameters. Our second major contribution is evaluation of our RMAB system
in collaboration with an NGO, via a real-world service quality improvement
study. The study compared strategies for optimizing service calls to 23003
participants over a period of 7 weeks to reduce engagement drops. We show that
the RMAB group provides statistically significant improvement over other
comparison groups, reducing ~ 30% engagement drops. To the best of our
knowledge, this is the first study demonstrating the utility of RMABs in real
world public health settings. We are transitioning our RMAB system to the NGO
for real-world use.
