Although policymakers have recently tended to call for longer school days or years, such reforms might be ineffective or counterproductive if they fail to take into account the interactions between time and other determinants of learning, including the role of the student in allocating time. Research has shown that the amount of learning is a function of capacity, effort, time, and quality of resources. Since effort is a variable determined by the student, means must be found to increase it by developing motivators either intrinsic or extrinsic to the curriculum. Extrinsic motivators, which seem to be losing their appeal to students, include rewards provided by parents, school and society; expectations of economic success; and fear of economic failure. Extrinsic motivators are difficult to manipulate. Cost analysis indicates that investing in upgrading the quality of teaching resources would cost less than increasing school hours and student workloads and would enhance learning. Furthermore, no good evidence suggests that adding days to the school year improves performance; even so, many states are making such additions. More research is needed before sweeping reforms can be justified. (FWR)