How to Calculate the productivity multiplier?
$begingroup$
Given a Cobb Douglas
$Y_t = A (K_t^alpha L_t^{1-alpha}) $
$ K_{t+1} = sY_t + (1-delta) K_t$
How do we get the multiplier on productivity to be equal to $ frac{1}{1-alpha}$?
I understand that if productivity increases, output increases, thus we get more capital and thereby more output and so on. But I can't reach this multiplier.
My Attempt:
If have x increase in A,
then
$Y_t=(1+x)A (K_t^alpha L_t^{1-alpha}) $
That is an x increase in Y.
$ K_{t+1} = s(1+x)A (K_t^alpha L_t^{1-alpha}) + (1-delta) K_t$
$Y_{t+1}=(1+x)A * K_{t+1}^alpha *L_{t+1}^{1-alpha} $
$Y_{t+1}= (1+x)A * (s(1+x)A (K_t^alpha L_t^{1-alpha}) + (1-delta) K_t)^alpha * L_{t+1}^{1-alpha} $
I think the increase here should be $x * alpha $ but I can't see it.
so that for a unit increase in productivity i.e x=1;
$Delta Y = 1 + alpha + alpha^2 +... =frac{1}{1-alpha} $
Also in the steady state we have,
$ Y = A^frac{1}{1-alpha} * frac{s}{delta}^frac{alpha}{1-alpha} * L$
taking logs we have that percentage change in A increases Y by $frac{1}{1-alpha}$.
macroeconomics economic-growth cobb-douglas solow growth-accounting
New contributor
$endgroup$
add a comment |
$begingroup$
Given a Cobb Douglas
$Y_t = A (K_t^alpha L_t^{1-alpha}) $
$ K_{t+1} = sY_t + (1-delta) K_t$
How do we get the multiplier on productivity to be equal to $ frac{1}{1-alpha}$?
I understand that if productivity increases, output increases, thus we get more capital and thereby more output and so on. But I can't reach this multiplier.
My Attempt:
If have x increase in A,
then
$Y_t=(1+x)A (K_t^alpha L_t^{1-alpha}) $
That is an x increase in Y.
$ K_{t+1} = s(1+x)A (K_t^alpha L_t^{1-alpha}) + (1-delta) K_t$
$Y_{t+1}=(1+x)A * K_{t+1}^alpha *L_{t+1}^{1-alpha} $
$Y_{t+1}= (1+x)A * (s(1+x)A (K_t^alpha L_t^{1-alpha}) + (1-delta) K_t)^alpha * L_{t+1}^{1-alpha} $
I think the increase here should be $x * alpha $ but I can't see it.
so that for a unit increase in productivity i.e x=1;
$Delta Y = 1 + alpha + alpha^2 +... =frac{1}{1-alpha} $
Also in the steady state we have,
$ Y = A^frac{1}{1-alpha} * frac{s}{delta}^frac{alpha}{1-alpha} * L$
taking logs we have that percentage change in A increases Y by $frac{1}{1-alpha}$.
macroeconomics economic-growth cobb-douglas solow growth-accounting
New contributor
$endgroup$
1
$begingroup$
You should show any work you've already done in attempting to solve this question.
$endgroup$
– Kenny LJ
4 hours ago
$begingroup$
@KennyLJ I updated with my attempt
$endgroup$
– Faye
4 hours ago
add a comment |
$begingroup$
Given a Cobb Douglas
$Y_t = A (K_t^alpha L_t^{1-alpha}) $
$ K_{t+1} = sY_t + (1-delta) K_t$
How do we get the multiplier on productivity to be equal to $ frac{1}{1-alpha}$?
I understand that if productivity increases, output increases, thus we get more capital and thereby more output and so on. But I can't reach this multiplier.
My Attempt:
If have x increase in A,
then
$Y_t=(1+x)A (K_t^alpha L_t^{1-alpha}) $
That is an x increase in Y.
$ K_{t+1} = s(1+x)A (K_t^alpha L_t^{1-alpha}) + (1-delta) K_t$
$Y_{t+1}=(1+x)A * K_{t+1}^alpha *L_{t+1}^{1-alpha} $
$Y_{t+1}= (1+x)A * (s(1+x)A (K_t^alpha L_t^{1-alpha}) + (1-delta) K_t)^alpha * L_{t+1}^{1-alpha} $
I think the increase here should be $x * alpha $ but I can't see it.
so that for a unit increase in productivity i.e x=1;
$Delta Y = 1 + alpha + alpha^2 +... =frac{1}{1-alpha} $
Also in the steady state we have,
$ Y = A^frac{1}{1-alpha} * frac{s}{delta}^frac{alpha}{1-alpha} * L$
taking logs we have that percentage change in A increases Y by $frac{1}{1-alpha}$.
macroeconomics economic-growth cobb-douglas solow growth-accounting
New contributor
$endgroup$
Given a Cobb Douglas
$Y_t = A (K_t^alpha L_t^{1-alpha}) $
$ K_{t+1} = sY_t + (1-delta) K_t$
How do we get the multiplier on productivity to be equal to $ frac{1}{1-alpha}$?
I understand that if productivity increases, output increases, thus we get more capital and thereby more output and so on. But I can't reach this multiplier.
My Attempt:
If have x increase in A,
then
$Y_t=(1+x)A (K_t^alpha L_t^{1-alpha}) $
That is an x increase in Y.
$ K_{t+1} = s(1+x)A (K_t^alpha L_t^{1-alpha}) + (1-delta) K_t$
$Y_{t+1}=(1+x)A * K_{t+1}^alpha *L_{t+1}^{1-alpha} $
$Y_{t+1}= (1+x)A * (s(1+x)A (K_t^alpha L_t^{1-alpha}) + (1-delta) K_t)^alpha * L_{t+1}^{1-alpha} $
I think the increase here should be $x * alpha $ but I can't see it.
so that for a unit increase in productivity i.e x=1;
$Delta Y = 1 + alpha + alpha^2 +... =frac{1}{1-alpha} $
Also in the steady state we have,
$ Y = A^frac{1}{1-alpha} * frac{s}{delta}^frac{alpha}{1-alpha} * L$
taking logs we have that percentage change in A increases Y by $frac{1}{1-alpha}$.
macroeconomics economic-growth cobb-douglas solow growth-accounting
macroeconomics economic-growth cobb-douglas solow growth-accounting
New contributor
New contributor
edited 3 hours ago
Kenny LJ
4,86421644
4,86421644
New contributor
asked 5 hours ago
FayeFaye
1084
1084
New contributor
New contributor
1
$begingroup$
You should show any work you've already done in attempting to solve this question.
$endgroup$
– Kenny LJ
4 hours ago
$begingroup$
@KennyLJ I updated with my attempt
$endgroup$
– Faye
4 hours ago
add a comment |
1
$begingroup$
You should show any work you've already done in attempting to solve this question.
$endgroup$
– Kenny LJ
4 hours ago
$begingroup$
@KennyLJ I updated with my attempt
$endgroup$
– Faye
4 hours ago
1
1
$begingroup$
You should show any work you've already done in attempting to solve this question.
$endgroup$
– Kenny LJ
4 hours ago
$begingroup$
You should show any work you've already done in attempting to solve this question.
$endgroup$
– Kenny LJ
4 hours ago
$begingroup$
@KennyLJ I updated with my attempt
$endgroup$
– Faye
4 hours ago
$begingroup$
@KennyLJ I updated with my attempt
$endgroup$
– Faye
4 hours ago
add a comment |
1 Answer
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$begingroup$
Let $y=Y/L$ and $k=K/L$ be the per-worker levels of output and capital. Observe that $y=Ak^alpha$.
Steady state is given by: $$k^*=sy^*+(1-delta)k^*,$$ or $$k^*=sA(k^*)^alpha+(1-delta)k^*.$$
Doing the algebra: $$k^*=left(frac{sA}{delta}right)^{frac{1}{1-alpha}}.$$
And: $$y^*=Aleft(frac{sA}{delta}right)^{frac{alpha}{1-alpha}}=A^{frac{1}{1-alpha}}left(frac{s}{delta}right)^{frac{alpha}{1-alpha}}.$$
I am not sure what is meant by the "multiplier on productivity". I would interpret this term to be the answer to the question, "Given a small unit change in $A$, what is the resultant change in $y^*$?" That is, the following expression: $$frac{partial y^*}{partial A}=frac{1}{1-alpha}A^{frac{alpha}{1-alpha}}left(frac{s}{delta}right)^{frac{alpha}{1-alpha}}.$$
However, clearly, this does not correspond to your desired answer. So I suspect what is really meant is the elasticity of $y^*$ with respect to $A$: $$frac{partial y^*}{partial A}div frac{y^*}{A}=frac{1}{1-alpha}.$$
$endgroup$
add a comment |
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$begingroup$
Let $y=Y/L$ and $k=K/L$ be the per-worker levels of output and capital. Observe that $y=Ak^alpha$.
Steady state is given by: $$k^*=sy^*+(1-delta)k^*,$$ or $$k^*=sA(k^*)^alpha+(1-delta)k^*.$$
Doing the algebra: $$k^*=left(frac{sA}{delta}right)^{frac{1}{1-alpha}}.$$
And: $$y^*=Aleft(frac{sA}{delta}right)^{frac{alpha}{1-alpha}}=A^{frac{1}{1-alpha}}left(frac{s}{delta}right)^{frac{alpha}{1-alpha}}.$$
I am not sure what is meant by the "multiplier on productivity". I would interpret this term to be the answer to the question, "Given a small unit change in $A$, what is the resultant change in $y^*$?" That is, the following expression: $$frac{partial y^*}{partial A}=frac{1}{1-alpha}A^{frac{alpha}{1-alpha}}left(frac{s}{delta}right)^{frac{alpha}{1-alpha}}.$$
However, clearly, this does not correspond to your desired answer. So I suspect what is really meant is the elasticity of $y^*$ with respect to $A$: $$frac{partial y^*}{partial A}div frac{y^*}{A}=frac{1}{1-alpha}.$$
$endgroup$
add a comment |
$begingroup$
Let $y=Y/L$ and $k=K/L$ be the per-worker levels of output and capital. Observe that $y=Ak^alpha$.
Steady state is given by: $$k^*=sy^*+(1-delta)k^*,$$ or $$k^*=sA(k^*)^alpha+(1-delta)k^*.$$
Doing the algebra: $$k^*=left(frac{sA}{delta}right)^{frac{1}{1-alpha}}.$$
And: $$y^*=Aleft(frac{sA}{delta}right)^{frac{alpha}{1-alpha}}=A^{frac{1}{1-alpha}}left(frac{s}{delta}right)^{frac{alpha}{1-alpha}}.$$
I am not sure what is meant by the "multiplier on productivity". I would interpret this term to be the answer to the question, "Given a small unit change in $A$, what is the resultant change in $y^*$?" That is, the following expression: $$frac{partial y^*}{partial A}=frac{1}{1-alpha}A^{frac{alpha}{1-alpha}}left(frac{s}{delta}right)^{frac{alpha}{1-alpha}}.$$
However, clearly, this does not correspond to your desired answer. So I suspect what is really meant is the elasticity of $y^*$ with respect to $A$: $$frac{partial y^*}{partial A}div frac{y^*}{A}=frac{1}{1-alpha}.$$
$endgroup$
add a comment |
$begingroup$
Let $y=Y/L$ and $k=K/L$ be the per-worker levels of output and capital. Observe that $y=Ak^alpha$.
Steady state is given by: $$k^*=sy^*+(1-delta)k^*,$$ or $$k^*=sA(k^*)^alpha+(1-delta)k^*.$$
Doing the algebra: $$k^*=left(frac{sA}{delta}right)^{frac{1}{1-alpha}}.$$
And: $$y^*=Aleft(frac{sA}{delta}right)^{frac{alpha}{1-alpha}}=A^{frac{1}{1-alpha}}left(frac{s}{delta}right)^{frac{alpha}{1-alpha}}.$$
I am not sure what is meant by the "multiplier on productivity". I would interpret this term to be the answer to the question, "Given a small unit change in $A$, what is the resultant change in $y^*$?" That is, the following expression: $$frac{partial y^*}{partial A}=frac{1}{1-alpha}A^{frac{alpha}{1-alpha}}left(frac{s}{delta}right)^{frac{alpha}{1-alpha}}.$$
However, clearly, this does not correspond to your desired answer. So I suspect what is really meant is the elasticity of $y^*$ with respect to $A$: $$frac{partial y^*}{partial A}div frac{y^*}{A}=frac{1}{1-alpha}.$$
$endgroup$
Let $y=Y/L$ and $k=K/L$ be the per-worker levels of output and capital. Observe that $y=Ak^alpha$.
Steady state is given by: $$k^*=sy^*+(1-delta)k^*,$$ or $$k^*=sA(k^*)^alpha+(1-delta)k^*.$$
Doing the algebra: $$k^*=left(frac{sA}{delta}right)^{frac{1}{1-alpha}}.$$
And: $$y^*=Aleft(frac{sA}{delta}right)^{frac{alpha}{1-alpha}}=A^{frac{1}{1-alpha}}left(frac{s}{delta}right)^{frac{alpha}{1-alpha}}.$$
I am not sure what is meant by the "multiplier on productivity". I would interpret this term to be the answer to the question, "Given a small unit change in $A$, what is the resultant change in $y^*$?" That is, the following expression: $$frac{partial y^*}{partial A}=frac{1}{1-alpha}A^{frac{alpha}{1-alpha}}left(frac{s}{delta}right)^{frac{alpha}{1-alpha}}.$$
However, clearly, this does not correspond to your desired answer. So I suspect what is really meant is the elasticity of $y^*$ with respect to $A$: $$frac{partial y^*}{partial A}div frac{y^*}{A}=frac{1}{1-alpha}.$$
answered 3 hours ago
Kenny LJKenny LJ
4,86421644
4,86421644
add a comment |
add a comment |
Faye is a new contributor. Be nice, and check out our Code of Conduct.
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Faye is a new contributor. Be nice, and check out our Code of Conduct.
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1
$begingroup$
You should show any work you've already done in attempting to solve this question.
$endgroup$
– Kenny LJ
4 hours ago
$begingroup$
@KennyLJ I updated with my attempt
$endgroup$
– Faye
4 hours ago