Observation equivalence holds in the hyperbolic discounting models such as Laibson (1996), Barro (1999), and Krusell et al (2002). We study a hyperbolic discounting model where the policy function cannot be replicated by a geometric discounting model. Under the logarithmic utility and Cobb-Douglas production, we obtain the explicit solution for consumer's consumption-saving decision. Different from the literatures of exponential discounting, our model shows that the habit persistence affects consumer''s consumption-saving decision. Therefore, observational equivalence does not hold in our hyperbolic discounting model.

This paper examines the efficiency in resource allocation in China. We estimate production functions at the provincial level and use these functions to compute time series for marginal products of capital and labor. We found that dispersion in the marginal product of capital declined from 1970 to 1984 and then became stable afterward, whereas the dispersion in the marginal product of labor declined initially but the trend has been reversed since 1993. We argue that this reversal may indicate any of the following: (1) policy-driven labor migration adding to labor market inefficiency; (2) the presence of increasing returns in labor; and (3) both capital and labor having become mobile since 1993.