7 ms·

You would only expect that if the shrinkage is entirely in non-productive members of the population -- unemployed, retired, etc. If population is shrinking at r

You would only expect that if the shrinkage is entirely in non-productive members of the population -- unemployed, retired, etc. If population is shrinking at random, you would expect the GDP to also drop at a similar rate as productive members are removed.

koolba 9y ago
Who said it's random? Productive people earn more and earning more is correlated with longer life.
- jdmichal 9y ago
  I certainly didn't, if that's your implication. Population decline due to low birth rate is mostly going to be on the tailing end of population age. You would expect tailing-end losses should generally skew towards retired non-productive members. However, that's not the only way to get population losses. Epidemics would be probably be skewed on economic indicators -- Lower class -> higher density -> higher infection rate. War would be skewed towards younger ages -- recruited soldiers in that 18-25 bracket that are on the front lines. Different causes will have differing effects on the population and different expected effects on GDP. You can't just generalize it to, "Wouldn't you expect GDP per capita to grow as population shrinks?" Which is what the original comment I replied to did.
  - thaumasiotes 9y ago
    > Population decline due to low birth rate is mostly going to be on the tailing end of population age. You would expect tailing-end losses should generally skew towards retired non-productive members. I don't follow. Population decline among old people is due to death. Population decline due to low birth rate occurs at the opposite end of the age spectrum, among babies. Those losses start among unproductive children and mature over time into losses among productive young workers.
    - deleted 9y ago
      [deleted]
    - jdmichal 9y ago
      The population curve will eventually skew, but that's not indicative of where productivity losses are happening. You don't count people that weren't born in productivity, then call it a loss. You lose productivity when a real person loses the ability to produce.
      - thaumasiotes 9y ago
        "Productivity loss" or "population decline"? Population decline from low birth rates occurs in people that weren't born. If you segment the population by age, this will be obvious -- compare the population figures to the same figures for the hypothetical situation where birth rates are higher, and you'll see that the numbers that are lower in reality than in hypotheticality are those for the young segments. Old age groups won't decline from low birth rates until all younger age groups already have. And from the perspective of losses to GDP, this is what's relevant. If birth rates decline starting in 1960, that has no effect on the population of people who were born in 1930. Their contribution to GDP will be just as it was always going to be. But the cohort born in 1980 will be much less productive, because it is smaller than it should have been, and that shows up in 2000 as a loss of young workers (compared to predictions), not old workers. > You don't count people that weren't born in productivity, then call it a loss. You do if you're arguing that losses to GDP are explained by lower birth rates.
        jdmichal 9y ago
        I agree with everything you said, except for the one axiom you state that everything else relies on: "But the cohort born in 1980 will be much less productive, because it is smaller than it should have been, and that shows up in 2000 as a loss of young workers (compared to predictions), not old workers." (Emphasis mine.) What defines what a group should have been? Predictions. But I've never heard of anyone calling a wrong prediction "losses" or "gains" before. If I'm predicted to sell a million units, and I only sell half that, did I "lose" half my sales? If a stock is predicted to go up a point, but goes down a point instead, did it "lose" two points? Comparing what materialized as reality with predictions is a perfectly fine thing to do. But differences between the two are just wrong predictions, not gains and losses. You just simply can't lose something you never had.
danmaz74 9y ago
Not if the fewer productive members have more capital / more productive jobs to do on average
- jdmichal 9y ago
  Then that's no longer random...
  - danmaz74 9y ago
    The population may shrink randomly, but the survivors will move from less productive (and less paid) jobs to more productive (and more paid) jobs.
    - jdmichal 9y ago
      Ah, yes I misread your comment. It's true; the picture is never static.

koolba 9y ago

Who said it's random? Productive people earn more and earning more is correlated with longer life.

jdmichal 9y ago
I certainly didn't, if that's your implication. Population decline due to low birth rate is mostly going to be on the tailing end of population age. You would expect tailing-end losses should generally skew towards retired non-productive members. However, that's not the only way to get population losses. Epidemics would be probably be skewed on economic indicators -- Lower class -> higher density -> higher infection rate. War would be skewed towards younger ages -- recruited soldiers in that 18-25 bracket that are on the front lines. Different causes will have differing effects on the population and different expected effects on GDP. You can't just generalize it to, "Wouldn't you expect GDP per capita to grow as population shrinks?" Which is what the original comment I replied to did.
- thaumasiotes 9y ago
  > Population decline due to low birth rate is mostly going to be on the tailing end of population age. You would expect tailing-end losses should generally skew towards retired non-productive members. I don't follow. Population decline among old people is due to death. Population decline due to low birth rate occurs at the opposite end of the age spectrum, among babies. Those losses start among unproductive children and mature over time into losses among productive young workers.
  - deleted 9y ago
    [deleted]
  - jdmichal 9y ago
    The population curve will eventually skew, but that's not indicative of where productivity losses are happening. You don't count people that weren't born in productivity, then call it a loss. You lose productivity when a real person loses the ability to produce.
    - thaumasiotes 9y ago
      "Productivity loss" or "population decline"? Population decline from low birth rates occurs in people that weren't born. If you segment the population by age, this will be obvious -- compare the population figures to the same figures for the hypothetical situation where birth rates are higher, and you'll see that the numbers that are lower in reality than in hypotheticality are those for the young segments. Old age groups won't decline from low birth rates until all younger age groups already have. And from the perspective of losses to GDP, this is what's relevant. If birth rates decline starting in 1960, that has no effect on the population of people who were born in 1930. Their contribution to GDP will be just as it was always going to be. But the cohort born in 1980 will be much less productive, because it is smaller than it should have been, and that shows up in 2000 as a loss of young workers (compared to predictions), not old workers. > You don't count people that weren't born in productivity, then call it a loss. You do if you're arguing that losses to GDP are explained by lower birth rates.
      - jdmichal 9y ago
        I agree with everything you said, except for the one axiom you state that everything else relies on: "But the cohort born in 1980 will be much less productive, because it is smaller than it should have been, and that shows up in 2000 as a loss of young workers (compared to predictions), not old workers." (Emphasis mine.) What defines what a group should have been? Predictions. But I've never heard of anyone calling a wrong prediction "losses" or "gains" before. If I'm predicted to sell a million units, and I only sell half that, did I "lose" half my sales? If a stock is predicted to go up a point, but goes down a point instead, did it "lose" two points? Comparing what materialized as reality with predictions is a perfectly fine thing to do. But differences between the two are just wrong predictions, not gains and losses. You just simply can't lose something you never had.

danmaz74 9y ago

Not if the fewer productive members have more capital / more productive jobs to do on average

jdmichal 9y ago
Then that's no longer random...
- danmaz74 9y ago
  The population may shrink randomly, but the survivors will move from less productive (and less paid) jobs to more productive (and more paid) jobs.
  - jdmichal 9y ago
    Ah, yes I misread your comment. It's true; the picture is never static.