My own book, SSFP, offers this about this groundbreaking book:
The number of late-to-mid-career workers in an industrial economy. Harry S. Dent, Jr., Ph.D. and James V. Smith, Jr. did the groundbreaking work on this factor (Dent 1993). They found that 49-year-olds (give or take five years or so) are the engine of modern economies far more powerfully than any other age group; they drive corporate profits and stock price growth. These people are at or near their peak value (profitability on their talent) to companies, they spend far more than any other demographic group, save (and especially buy stocks) more than any other demographic, they contribute more to social health and welfare plans than any other. In contrast, people in older demographics draw from social welfare plans (health plans, especially), they directly drive down stock values by selling off their equities (both for income and to reduce equities exposure), and their productivity approaches zero due to retiring. What Dent observed in public birth records, and related to stock price movements over the last century because the economic power of these “49-ers” is proven causal to economic trends, is this: The birth rate, from which we can accurately predict 49-ers numbers, has not changed only gradually as most people assume; it changes dramatically in reaction to booms and busts existing at the time of conception; that is, when times are good, people have more babies and vice versa.
There is almost a one-to-one correlation between and the number of these 49-ers in the economy (height of the gray) and the stock price trends emerging (The Dow stock price index) as the demographic shows major changes. Birth rate is a leading indicator of the Dow, especially looking forward to the number of 49 year-olds in the economy. This strong correlation extends farther back even than the graph below shows, as far back as 1920. The Great Depression was caused by reducing demand because of a 1928 reversal of growth in the population of peak-earners. If investors begin to believe this relationship (it is causal to a strong degree), they will anticipate downturns and upturns in stock prices. This factor is strong, but impossible to model with all other factors such as oil discoveries, political changes, tax changes, and many others that are unpredictable but also very influential. But one thing is certain: This demographic factor has been increasingly a negative leading indicator of economic growth and stock prices since 2010; it will bottom out in 2022, followed by a 19-year upswing.
“We had a recession in 2008 and recovery well past 2010,” you may retort, “and Dent predicted a boom from 2001 through 2008 that did not materialize.” Yes but anomalous factors overcame and obscured this demographic factor: the 9/11 Terror Attacks and ensuing worldwide enhanced security costs, followed by a credit crisis due to mendacity in the secondary mortgage market; we kicked the can down the road in 2008 with trillions in borrowed money pumped into the economy. The lesson of Dent’s work remains: Though demographic risk, as I will call it, can be overcome by other, adequately strong, factors (low oil prices, I hope) and its strength has not yet been reliably modeled, most economists know it to be a profound and causal factor for stock price trends and to be the only such factor that can be predicted fifty years into the future. More at HSDent.com