barrett@ruth:~$ /economics

Models of Production

solow

introduction

The Solow Model is an economic model of production that incorporates the incorporates the idea of capital accumulation. Based on the Cobb-Douglas production function, the Solow Model describes production as follows: \[Y_t=F(K_t,L_t)=\bar{A}K_t^\alpha L_t^{1-\alpha}\] With:

  • \(\bar{A}\): total factor productivity (TFP)
  • \(\alpha\): capital's share of output—usually \(1/3\) based on empirical data

In this simple model, the following statements describe the economy:

  1. Output is either saved or consumed; in other words, savings equals investment
  2. Capital accumulates according to investment \(I_t\) and depreciation \(\bar{d}\), beginning with \(K_0\)
  3. Labor \(L_t\) is time-independent
  4. A savings rate \(\bar{s}\) describes the invested portion of total output

Including the production function, these four ideas encapsulate the Solow Model:

  1. \(C_t + I_t = Y_t\)
  2. \(\Delta K_{t+1} = I_t - \bar{d} K_t\)
  1. \(L_t = \bar{L}\)
  2. \(I_t = \bar{s} Y_t\)

solving the model

Visualizing the model, namely output as a function of capital, provides helpful intuition before solving it.

Letting \((L_t,\alpha)=(\bar{L}, \frac{1}{3})\), it follows that \(Y_t=F(K_t,L_t)=\bar{A}K_t^{\frac{1}{3}} \bar{L_t}^{\frac{2}{3}}\). Utilizing this simplification and its graphical representation below, output is clearly characterized by the cube root of capital:

conclusions

hello conclusions

romer

romer-solow