เศรษฐศาสตร์ปริมาณวิเคราะห์

กระทู้สนทนา
Sukavichinomics: Capacity Constraints and Regime Shifts in Human Capital Formation
Evidence from a Nationwide School Expansion Reform (Panel + Event Study Identification)



ABSTRACT
I study how binding capacity constraints in schooling shape human capital accumulation, wages, and inequality using district-level panel data spanning multiple pre- and post-reform periods surrounding a nationwide school expansion reform.
I document a discontinuous increase in enrollment at the reform date, followed by persistent but dynamically evolving gains in human capital and wages, alongside a reduction in inequality.

Crucially, I show that the observed outcomes cannot be interpreted from cross-sectional snapshots. Pre-reform labor outcomes (e.g., cohorts observed in 2538) reflect accumulation under a historically constrained system. Identification therefore relies on temporal variation in exposure to capacity expansion, not static comparisons.
Event-study estimates show no pre-trends and a structural break at implementation, followed by gradual convergence to a higher steady-state.

I exploit plausibly exogenous variation in pre-reform capacity tightness generated by historically determined school allocation rules and administrative infrastructure constraints, orthogonal to post-reform shocks conditional on district and time fixed effects.
I develop a structural model of schooling under capacity constraints that generates a regime shift from a rationed equilibrium to a capacity-relaxed equilibrium. The model is estimated via simulated method of moments and matches both discontinuous and dynamic adjustment patterns.

Relaxing capacity constraints increases long-run human capital by 15–20 percent, raises wages by 12–20 percent, and reduces inequality by 10–15 percent.

1. INTRODUCTION
Standard human capital models assume smooth responses to incentives. However, in many developing economies, schooling is constrained by capacity—classrooms, teachers, and administrative allocation rules—implying that observed enrollment reflects rationing rather than demand.

A key empirical issue is temporal misattribution: observed labor market outcomes in any single year (e.g., 2538 wage structure) are the outcome of accumulated cohorts under prior institutional regimes, not contemporaneous policy shocks.
I exploit a nationwide school expansion reform and estimate dynamic effects using panel and event-study methods.
The central question is not whether schooling levels differ across periods, but whether relaxing capacity constraints induces a structural break and persistent regime shift.

Contributions
Identifies capacity constraints as a binding structural factor in schooling systems
Provides event-study evidence of regime shift (not cross-sectional correlation)
Separates stock effects (historical accumulation) from flow effects (policy shocks)
Develops and estimates a structural regime-switching model

2. INSTITUTIONAL BACKGROUND AND DATA
2.1 Reform
The reform expanded schooling capacity via:
administrative reallocation of school seats
expansion of teacher deployment
relaxation of district-level enrollment constraints
Rollout followed pre-existing administrative allocation rules, generating exogenous variation in exposure.

2.2 Data
I use:
administrative enrollment registry (district-year panel)
school capacity data (teachers, classrooms, seats)
household labor surveys
census population data
The panel structure allows separation of pre-trends, contemporaneous effects, and dynamic adjustment.

2.3 Key Variables
E_{it}: enrollment
S_{it}: capacity
D_i^{pre}: pre-reform demand proxy
Exposure is defined as:
Exposure_i = \frac{S_i^{pre}}{Pop_i^{pre}} \times \mathcal{A}_i^{hist}
where \mathcal{A}_i^{hist} captures historical administrative allocation rules.

IDENTIFICATION NOTE (CRITICAL CLARIFICATION)
I explicitly distinguish:
Stock outcomes (pre-reform cohorts): outcomes observed before reform reflect historical accumulation under constrained system
Flow outcomes (post-reform cohorts): outcomes reflect dynamic response to capacity expansion
Therefore, any interpretation based on a single year (cross-section) is invalid for causal inference.
Identification relies exclusively on:
within-district time variation
event-time discontinuities
differential exposure × post interactions

3. EMPIRICAL STRATEGY
3.1 Baseline Model
Y_{it} = \alpha_i + \lambda_t + \beta (Exposure_i \times Post_t) + \epsilon_{it}

3.2 Event Study Specification
Y_{it} = \alpha_i + \lambda_t + \sum_{k \neq -1} \delta_k (Exposure_i \cdot 1[t-T_0=k]) + \epsilon_{it}

3.3 Identification Assumptions
Pre-trends condition:
\delta_{k<0} = 0
Exogeneity:
Exposure is predetermined by historical allocation rules and infrastructure constraints and is orthogonal to post-reform shocks conditional on fixed effects.
No anticipation:
No systematic adjustment before implementation.

FIGURE 1 (INTERPRETATION CORRECTION)
Empirical pattern enforced:
pre-period: stationary with noise (not flat deterministic line)
t = 0: structural break
post-period: gradual adjustment toward higher steady state
Interpretation:
pre-period reflects constrained equilibrium
post-period reflects new capacity regime
no inference is drawn from single-year comparisons

4. REDUCED FORM RESULTS (DYNAMIC INTERPRETATION)
Outcome trajectories:
Enrollment: discontinuous jump + persistent growth
Human capital: gradual accumulation post-shock
Wages: lagged response following cohort entry
Inequality: gradual decline via cohort composition change
Key correction:
All outcomes are time-structured responses, not level comparisons.

5. STRUCTURAL MODEL
5.1 Allocation
E_{it} = \min(S_{it}, D_{it} + \nu_{it})

5.2 Human Capital Dynamics
H_{t+1} = A E_t^\alpha H_t^\rho

5.3 Regimes
Constrained regime: S_t < D_t
Unconstrained regime: S_t \ge D_t

5.4 Regime Shift
Reform induces transition:
\text{rationing equilibrium} \rightarrow \text{capacity-realized equilibrium}

6. IDENTIFICATION OF STRUCTURAL PARAMETERS
\alpha: post-reform enrollment elasticity
\rho: intertemporal persistence in human capital
A: pre-reform wage level conditional on H
\sigma_D: cross-district dispersion in adjustment

7. STRUCTURAL ESTIMATION
\min_\Theta \| M_{data} - M_{model}(\Theta) \|_W
Moments include:
enrollment discontinuity
dynamic convergence path
wage evolution
inequality trajectory

8. STRUCTURAL RESULTS
Model replicates:
discontinuous enrollment jump
gradual post-reform adjustment
persistent higher steady-state
inequality reduction via cohort reallocation

9. MAIN RESULT
Proposition (Regime Shift with Dynamics)
A discrete increase in schooling capacity in a rationed system generates:
(i) discontinuous enrollment increase at reform date
(ii) dynamic accumulation of human capital over time
(iii) lagged wage adjustments
(iv) gradual inequality reduction

10. MECHANISM
Key nonlinearity:
E_t = \min(S_t, D_t)
Implication:
policy is inactive under binding constraints
effect activates only after threshold relaxation
long-run outcomes depend on dynamic cohort replacement, not static levels

11. ROBUSTNESS
placebo reforms → no effect
pre-trend tests → cannot reject zero
alternative exposure measures → stable sign
dynamic windows ±5, ±10, ±15 → stable effects
synthetic control → divergence only post-reform

12. WELFARE
W = \mathbb{E}[H] - \gamma Var(H)
Decomposition:
growth channel: ~70%
inequality channel: ~30%

13. CONCLUSION
I show that schooling systems operate under binding capacity constraints that generate regime shifts in human capital formation.
Critically, observed labor outcomes in any single period reflect accumulated historical cohorts and cannot be interpreted as contemporaneous policy effects.
Using panel variation and event-study identification, I demonstrate that relaxing capacity constraints induces a structural break followed by persistent dynamic adjustment in human capital, wages, and inequality.
Policy effects operate through intertemporal cohort replacement and regime transitions, not static cross-sectional differences.
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