Demographic and fertility models

What is Balanced Growth Path

all variables grow at a constant rate

steps to find balanced growth path

• find yt from Yt

• Take logs both sides

• use special log fact to get growth rate

What is Y.t/yt also know as

gy

Special Log trick

dlogx/dt = (dx/dt)/dt = gx

growth rate of z if z=xy

gz = gx + gy

growth rate of z if z=x/y

gz = gx - gy

growth rate of z if z=x^b

bgx

Balanced Growth path method for At

to get gA , get At as the subject , take logs . use log trick to then get gA

Graph of semi endogenous growth model

Problem with romer model

• dimishing returns to ideas not present eventhough seen in data

Y axis of graph

A*t/At

X axis

La,t/At^B

types of shift on graph

correctional , shift down of flat growth rate, pivot of diagonal due to changes in Z