South Asia Economic Focus

Page 108

shifting gears

Appendix 2 Long-term growth model

The Long-term Growth Model (Loayza and Pennings 2018) is based on Solow (1956), Swan (1956), and Hevia and Loayza (2012). The economy consists of a single sector that produces output using physical capital ​Kt​ ​ ​and effective labor ​ht​ ​ ​Lt​ ​​.​ ​At​ ​ denotes total factor productivity (TFP), which determines the aggregate efficiency of the economy. The relationship between inputs and output is governed by the CobbDouglas production function given by: ​Yt​ ​  = ​At ​​ ​Kt​ 1−β ​  ​ ​(​ht​ ​ ​Lt​ ​)​ β​ ​ where ​β​is the aggregate labor share of income, while effective labor is decomposed into human capital per worker ​ht​ ​ ​and the number of workers ​Lt​ ​. The total number of workers can be written as: ​Lt​ ​  = ​ρt​ ​ ​ωt​ ​ ​Nt​ ​ where ​ρt​ ​is the participation rate, ​ωt​ ​is the working age to total population ratio, and​ N​t ​is the total population. Physical capital in the next period ​Kt+1 ​  ​ is formed by undepreciated capital ​(1 − δ)​ ​Kt​ ​ and new investment ​It​ ​​: ​Kt+1 ​  ​  =  (​ 1 − δ)​ ​Kt​ ​+ ​It​ ​ Headline GDP growth ​gy, t+1 ​  ​ ​could be decomposed using a log-linear approximation into different growth fundamentals, where ​gx, t+1 ​  ​ ​is the growth rate of factor x from t to t+1: 1 − β ​It​ ​ [ ​​Y​ ​ ​ ] t

​gy, t+1 ​  ​  = ​gA,t+1 ​  ​  + β​(​gh, t+1 ​  ​  + ​gω, t+1 ​  ​  + ​gρ, t+1  ​ ​)​  + ​ _ ​  _​K​  ​   ​ ​ ​ _   ​(1 − β)​δ + ​gN,t+1 ​  ​ ​Y​  ​​− t

t

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