IMF-税收征管改革收益的量化（英）-2023.11-42页_1mb

Quantifying the Revenue Yields from Tax Administration Reforms

This paper estimates the revenue impact of tax administration (TA) reforms using two methodologies:

1. Hausman-Taylor cross-country panel regression with endogenous time-invariant variables.
2. Event studies and difference-in-differences (DiD) with staggered reforms.

Key Findings

1. Revenue Yields from Overall TA Strength

• An increase in TA strength by 20 percentage points (from 40th to 60th percentile) is associated with:
  • 1.8% GDP higher tax revenue for EMs and LIDCs (ISORA OS index).
  • 1.4% GDP higher tax revenue (TADAT PAR index).
• Revenue gains increase over time, reaching 3% GDP after six years post-reform.

2. Effective Tax Administration Practices

• Top contributors to revenue gains (by practices):
  • Strengthening compliance risk management, public accountability, and establishing Large Taxpayer Offices (LTO).
  • Improving accountability and transparency and timely filing (TADAT indicators).
• ISORA and TADAT indexes show high correlations, indicating complementary measures.

3. Impact of Specific Reforms

• Using event studies, sustained TA reforms post-GFC increased tax revenues by 2-3% of GDP for EMs and LIDCs.
• Case studies (Jamaica, Rwanda, Senegal) confirm revenue gains rising to 3-4.7% GDP within 6 years.
• Gains peak after the 6th year, consistent with findings from aggregated and synthetic DiD methods.

4. Policy Recommendations

• Develop TA reforms comprehensively to leverage synergies between practices.
• Benchmark reforms using the IMF FAD TA Assessment and Yield Tool.
• Prudent fiscal projection requires conservative estimates and country-specific validation.

Methodology

• Panels: Longitudinal data with slow-moving TA indicators.
• Controls: Adjust for macroeconomic, structural, and tax policy variables.
• Innovations: Houseman-Taylor estimator with pretest instrumentation and three-stage event-study analysis.