The development of work incentives has been a perennial problem in planned economies. In China's countryside the pendulum has swung from emphasis on non-material and egalitarian incentives under Mao to the more individualistic incentives of the post-Mao era. In the late 1970s, China's new leaders introduced the production responsibility system (shengchon zerenzhi) which sought to motivate farmers by rewarding them for completing specific tasks. Both old and new measures have been used to implement this system. Cadres have borrowed certain work measurement methods attached to the old labour-day work payment system, operating since the mid 1950s, which fixed responsibility for tasks and awarded labour days when work was completed. But cadres have also adopted an entirely new work-payment system in which households negotiate with production teams to farm given parcels of land. These households agree to return a certain quantity of their crops to fulfil collective and state obligations and are then permitted to retain the surpluses for themselves. This new system is called baogan daohu (“full responsibility to household,” hereafter referred to as the baogan system). Sometimes the system is also referred to as the jiating lianchan chengbao zhi or the household responsibility system.