Historic debates about the measurement of capital are even more complicated in the case of education and human capital. As extensive research demonstrates, education resources are not consistently related to student performance in existing elementary and secondary schools. This inefficiency in public schools implies that spending and resource measures do not accurately capture variations in school quality. This finding then has clear implications for both education policy and economic research. Because school inputs are poor policy instruments, an alternative policy focus that appears much more productive is performance incentives related to student achievement.