The Hartz concept, also known as Hartz reforms or the Hartz plan, is a set of recommendations submitted by a committee on reforms to the German labour market in 2002. Named after the head of the committee, Peter Hartz, these recommendations went on to become part of the German government's Agenda 2010 series of reforms, known as Hartz I – Hartz IV. The committee devised thirteen "innovation modules", which recommended changes to the German labour market system. These were then gradually put into practice: The measures of Hartz I – III were undertaken between January 1, 2003, and 2004, while Hartz IV was implemented on January 1, 2005.