On the welfare significance of national product for economic growth and sustainable development

This paper formulates an investment value transversality condition in a continuous-time growth model, which characterizes competitive paths along which current net national product measures the welfare achieved along the path. This transversality condition requires that the present value of net investment goes to zero asymptotically. An example provided shows that, in general, competitive paths do not necessarily satisfy this condition. It is also shown that, in a standard growth model including an exhaustible resource as an essential factor of production, competitive paths always satisfy this condition. Implications regarding national income accounting procedures and sustainable development policies are discussed. JEL Classification Numbers: D90; O11; O41; Q32.