ATLAS Open Data: co-creation of educational resources

The ATLAS Open Data project aims to deliver open-access resources for education and outreach in High Energy Physics and related computer sciences. Because the resources -data, software and documentation-target students and instructors, they must be tested by students and instructors before being released. One of the most effective production ways we have found is to promote on-site and remote training schemes such as high-school work experience and summer schools programs, university projects and PhDs qualification tasks. Those programs and alliances allow the construction of a platform that relies on the expertise of ATLAS members and the invaluable contribution of students that help to test and build resources that hundreds of their peers use around the world. We present how multiple training programs inside and outside CERN helped and continue to help create the ATLAS Open Data project and the lessons learnt so far on how to continue implementing this kind of programs.