Smartphones are a revolutionary technology that has impacted public health for both good and ill. They have been linked to distracted driving, an epidemic of insomnia and an increasing inability to unplug from work. But smartphones also remind patients to take their medicine, help smokers quit and even act as daily fitness trackers. Functions like GPS and cameras allow for improved collection of health data.

Mobile phones don’t have to be smart to have a public health impact. They enable health workers to make inroads in remote areas of the world where many don’t have running water or even electricity but do have mobile phones. A recent Johns Hopkins Bloomberg School of Public Health study on family planning in rural India found that a smartphone app increased contraceptive use. The app helped married women in the region better understand contraceptive choices and led to an increase in the number of women using modern family planning methods.