An inter-experimental study group, DPHEP, was formed in 2009 to systematically investigate the technical and organisational aspects of data preservation and long-term analysis in high-energy physics, a subject which had hitherto lacked clarity in the field. The study group includes representation from all major high-energy physics collider-based experiments and laboratories, as well as computing centres and funding agencies. A major report was released in May 2012, greatly expanding on the ideas contained in a preliminary publication three years earlier, and providing a more solid set of recommendations, not only concerning data preservation and its implementation in high-energy physics, but also the future direction and organisational model of the study group. A brief description of the DPHEP Study Group and some of the key messages from the major report are presented.