OK, one more little piece on age and efficiency, and I promise I'll give this a miss for a while. This time it's from the EU Paper on the economic and financial market consequences of ageing. The paper doesn't examine the problme of age and productivity in any detail, but what little there is seems intuitively obvious to me:
While the central scenario for the EU assumes no change in the contribution of TFP to growth over the simulation period compared with the historical pattern, nevertheless it is important to underline the possibility that productivity growth could be adversely affected. These productivity concerns reflect the significantly weaker investment performance described earlier; evidence from income-age profiles which suggests that the marginal productivity of workers tends to start to decline in their early to mid 50’s; and worries that enthusiasm for reform and overall levels of dynamism and innovation in an economy may be detrimentally affected by having an ageing labour force.
This view is corroborated on the basis of results from the London Business School’s “Global Entrepreneurship Monitor” which covers 29 countries around the world (2 ½ billion people in total) and suggests that older societies tend to be less entrepreneurial, with evidence that the majority of “entrepreneurially active adults” are aged between 25 and 44.
Source: ECONOMIC AND FINANCIAL MARKET CONSEQUENCES OF AGEING POPULATIONS