As children of every age navigate the new world of devices, online games and social media sites, they are exposed to a variety of messages and to people interacting with them. In many circumstances online behaviors lead to unhealthy and dangerous choices. Our team of experts in measurement science, statistics and survey development has conducted research on children’s online behaviors and developed an online safety index to assess their exposure to risky situations. The index is currently being used in a randomized controlled trial to evaluate the impact of educational activities directed to high school students to improve knowledge about the risks of the online space. This project is funded by the United States National Institute of Justice.