The investment needed to provide services should be characterized by some unevenness as well as by high capital output ratio.

According to this formula the incremental capital output ratio can be computed by dividing the investment share in GDP by the rate of growth of GDP.

Their models combined Keynes's multiplier with an accelerator model of investment, and produced the simple result that growth equaled the savings rate divided by the capital output ratio (the amount of capital divided by the amount of output).