Internal medicine

eHealth

Intervention (counseling)

User engagement

Economic growth

Obesity

Internet privacy

World Wide Web

Nursing

Political science

Psychology

Health care

Economics

Psychological intervention

Overweight

mHealth

Childhood obesity

Computer science

Disadvantaged

Gerontology

Medicine

JMIR mhealth and uhealth

Background: Childhood obesity is an ongoing problem in developed countries that needs targeted prevention in the youngest age groups. Children in socioeconomically disadvantaged families are most at risk. Mobile health (mHealth) interventions offer a potential route to target these families because of its relatively low cost and high reach. The Growing healthy program was developed to provide evidence-based information on infant feeding from birth to 9 months via app or website. Understanding user engagement with these media is vital to developing successful interventions. Engagement is a complex, multifactorial concept that needs to move beyond simple metrics.

Assessing User Engagement of an mHealth Intervention: Development and Implementation of the Growing Healthy App Engagement Index