An Interactive Analysis using a Dynamic Stochastic General Equilibrium (DSGE) Model
Developed by: Dr. Muhammad Zeshan, PIDE Islamabad. Email: zeshan@pide.org.pk
Baseline (No Shock): Represents the economy's path in the absence of any new shocks.
Scenario 1: Agricultural Productivity Shock: Simulates a temporary change in agricultural productivity. A positive value represents a decline (e.g., bad harvest), while a negative value represents a boom (e.g., bumper crop).
Scenario 2: Extreme Weather (Capital Destruction): Models a one-time, unexpected destruction of the nation's capital stock. Only positive values are applicable.
Scenario 3: Monetary Policy Shock: Simulates an unexpected change in the central bank's policy interest rate. A positive value represents a rate hike, while a negative value represents a rate cut.
This chart shows the dynamic response of key macroeconomic variables over time following the selected shock.
This chart illustrates the impact of the shock on household welfare, particularly the poverty rate and consumption levels.
This graph summarizes the maximum percentage deviation from the baseline for key macro indicators within the simulation period.
This graph summarizes the maximum percentage deviation from the baseline for key micro indicators, showing the most severe impact on households.
The model is a standard New Keynesian DSGE framework adapted for Pakistan, featuring households, firms, and a government. Key equations include:
A representative household maximizes utility from consumption (C) relative to a habit stock (h), and leisure (1-L), subject to a budget constraint.
$$ \max E_0 \sum_{t=0}^{\infty} \beta^t \left( \frac{(C_t - hC_{t-1})^{1-\sigma}}{1-\sigma} - \frac{L_t^{1+\phi}}{1+\phi} \right) $$
Budget Constraint:
$$ P_t C_t + B_{t+1} \leq R_t B_t + W_t L_t + \Pi_t $$
Intermediate goods firms operate in a monopolistically competitive market with sticky prices (Calvo-pricing). They produce using a Cobb-Douglas technology with capital (K) and labor (L).
$$ Y_t(i) = A_t K_t(i)^{\alpha} L_t(i)^{1-\alpha} $$
Final good is a CES aggregate of intermediate goods.
The central bank follows a Taylor-type rule, reacting to inflation \( \pi_t \) and output gap \( \tilde{y}_t \).
$$ \frac{R_t}{R_{ss}} = \left( \frac{R_{t-1}}{R_{ss}} \right)^{\rho_R} \left[ \left( \frac{\pi_t}{\pi_{ss}} \right)^{\phi_{\pi}} \left( \frac{Y_t}{Y_{ss}} \right)^{\phi_y} \right]^{1-\rho_R} \exp(\varepsilon_{R,t}) $$
Agricultural Productivity Shock (\( A_{agri,t} \)):
$$ \log(A_{agri,t}) = \rho_A \log(A_{agri,t-1}) + \varepsilon_{A,t} $$
Capital Destruction Shock (\( \delta_t \)):
$$ K_t = (1 - \delta_t) K_{t-1}^{eff} + I_t $$
Where \( \delta_t \) is the depreciation rate, which spikes during an extreme weather event.
Parameter | Value | Description | Justification |
---|---|---|---|
\( \beta \) | 0.99 | Household discount factor | Standard value implying a 4% annual real interest rate. |
\( \sigma \) | 1.5 | Coefficient of relative risk aversion | Common in literature for emerging economies. |
\( \alpha \) | 0.50 | Capital share in production | Calibrated based on DSGE models for Pakistan. |
\( \delta \) | 0.0375 | Quarterly depreciation rate | Consistent with an annual depreciation rate of 15% used in DSGE models for Pakistan. |
\( \theta_p \) | 0.75 | Calvo price stickiness | Implies prices are fixed for an average of 4 quarters. |
\( \phi_{\pi} \) | 1.5 | Taylor rule inflation response | Standard value for ensuring macroeconomic stability. |
\( \phi_{y} \) | 0.25 | Taylor rule output gap response | Standard value. |
\( \rho_A \) | 0.85 | Persistence of productivity shock | Assumed high persistence for climate-related shocks. |