The accelerated adoption of digital technologies in people’s lives is creating unique opportunities to leverage routinely collected digital data and machine learning models to diagnose diseases before they become symptomatic. Like traditional tests, digital screening will likely generate cases of overdiagnosis and thereby harm some patients. Digital screening tests (such as detecting mood or sleep disorders from smartphone use patterns) are being developed faster than the ability to assess their value. The additional risks and benefits of these digital tests are not only a function of their accuracy; and it is important that such approaches be validated prospectively.