Social insurance, life insurance, and equilibrium in an OLG economy

국문 초록 (Abstract)

본 논문은 인구 고령화와 건강 위험의 증가가 초래하는 경제‧재정적 영향에 대응하기 위해, 공적 건강보험, 생명보험, 유산동기(bequest motive)의 상호작용이 세대 간 경제성과에 미치는 영향을 분석하는 두 가지 상이한 중첩세대(OLG) 모형을 개발한다. 전체적인 목적은 건강 충격, 의료비 지출 위험, 생존확률의 변화, 세대 간 이전 메커니즘이 가계의 최적 의사결정과 거시경제 균형에 어떠한 경로를 통해 영향을 미치는지를 이론적으로 규명하는 데 있다.
제2장은 건강 상태의 내생적 변화와 의료 접근성의 제약을 도입한 OLG 모형을 제시한다. 개인은 근로기와 은퇴기를 거치며 건강한 상태와 불건강한 상태를 오가고, 이에 따라 의료비 지출, 노동생산성, 생존확률이 결정된다. 공적 건강보험은 의료비의 일부를 보조함으로써 건강 위험을 완화하지만, 유동성 제약으로 인해 필요한 의료서비스를 충분히 이용하지 못할 가능성도 반영된다. 모형 분석 결과, 공적 건강보험의 보장성이 확대될수록 의료비 위험이 감소하고 가계의 precautionary saving 유인이 약화되며, 이는 소비 증가, 자본축적 감소, 균형이자율 하락과 같은 거시경제적 조정을 야기한다. 또한 사망률 변화, 건강 전이확률 변화, 보장 비율 조정 등 다양한 정책 변수 변화에 대한 민감도 분석을 통해, 공적 보험정책이 거시경제 안정성과 복지에 미치는 영향을 정량적으로 제시한다.
제3장은 민영 생명보험과 유산동기를 도입함으로써 공적 연금제도와 민간보험시장의 상호작용을 분석한다. 가계는 생존위험과 세대 연결성을 고려하여 소비, 저축, 생명보험 가입을 동시에 최적화하며, 생명보험은 사후소득 이전과 소비안정장치라는 이중적 역할을 수행한다. 분석 결과, 유산동기의 강도는 자본축적과 균형이자율을 크게 변화시키며, 근로세대·은퇴세대·유가족 간의 복지 배분에도 중요한 영향을 미친다. 또한 유족급여 수준, 은퇴자 생존율 변화, 생명보험 가입 행태 변화 등은 민간보험시장과 공적 연금제도 전반에 걸쳐 상호 연계된 조정효과를 발생시키는 것으로 나타났다.
본 논문은 공적 건강보험, 공적 연금, 민간 생명보험 제도를 상호 보완적으로 통합적으로 분석해야 한다는 점을 강조한다. 본 연구는 건강 위험의 내생적 진척, 의료 접근성 제약, 유산동기 등 미시적 요소를 거시경제 균형에 연결함으로써, 고령화가 빠르게 진행되는 경제에서 지속가능한 사회보험 설계에 유용한 정책적 함의를 제공한다.

다국어 초록 (Multilingual Abstract)

This dissertation develops two complementary overlapping-generations (OLG) models to analyze how public health insurance, public pensions, private life insurance, and bequest motives jointly shape intergenerational economic outcomes in aging economies. The overarching objective is to capture the channels through which health shocks, medical expenditure risk, longevity, and intergenerational transfers influence household optimization and macroeconomic equilibrium.
Chapter 2 introduces an OLG model with endogenous health dynamics and incomplete access to healthcare. Individuals transition between good and poor health during their working and retirement years, facing medical expenditures, productivity changes, and survival risks. Public health insurance alters these dynamics through subsidies that reduce effective health expenditure risk. The model incorporates liquidity constraints that may prevent individuals from consuming necessary medical care. The analysis demonstrates that expanding public coverage reduces precautionary savings, raises aggregate consumption, and lowers equilibrium interest rates. Numerical calibration shows how changes in mortality, transition probabilities, and coverage ratios reshape capital accumulation and macroeconomic stability.
Chapter 3 extends the OLG framework by incorporating private life insurance, bequest motives, and public pension benefits. Households choose consumption, saving, and life-insurance purchases while facing survival risk and intergenerational linkages. Within this structure, life insurance simultaneously serves as consumption smoothing and bequest transfer. The model identifies how bequest intensity influences capital accumulation, interest rates, and welfare distribution between workers, retirees, and dependents. Quantitative steady-state analysis reveals substantial interactions between public pensions and private insurance markets, including how changes in survivors’ benefits, retirees’ survival rates, and bequest preferences propagate through the macroeconomy.
Overall, the dissertation provides a unified macroeconomic perspective linking public health insurance, life insurance markets, and pension systems. The findings underscore that designing sustainable social insurance policies requires jointly considering public and private instruments, particularly in societies facing rapid population aging and increasing heterogeneity in health risk.

목차 (Table of Contents)

• 1 Introduction 1
• 2 Public Health Insurance and Precautionary Saving 4
• 2.1 Introduction 4
• 2.2 Literature Review . 6
• 2.3 Demographic structure 9
• 2.4 Decision of Individual . 12
• 2.4.1 Decision of Retirees Remaining in the Same Health Condition 12
• 2.4.2 Decision of Retirees Experiencing Health Deterioration 14
• 2.4.3 Decision of Workers in Good Health . 15
• 2.4.4 Decision of Workers in Poor Health . 16
• 2.5 Aggregate decision 18
• 2.6 Steady-state equilibrium . 22
• 2.7 Numerical analysis 27
• 2.7.1 Parameter values . 27
• 2.7.2 Base-case scenario 29
• 2.8 Sensitivty Analysis 31
• 2.8.1 Increase in mortality . 31
• 2.8.2 Decrease in mortality . 33
• 2.8.3 Changes in Transition Probabilities for Workers in Good Health 35
• 2.8.4 Changes in Transition Probabilities for Workers in Poor Health 36
• 2.8.5 Increase in health coverage ratio . 38
• 2.8.6 Decrease in health coverage ratio 39
• 2.8.7 Summary of Macroeconomic Outcomes . 39
• 2.9 Sub-conclusion 41
• 3 Life Insurance, Bequest and Social Security 43
• 3.1 Introduction 43
• 3.2 Population dynamics and utilities 48
• 3.2.1 Population dynamics . 48
• 3.2.2 Utilities 51
• 3.3 Household Optimization in the OLG Framework 54
• 3.3.1 Dependent's decision . 54
• 3.3.2 Retiree's decision . 56
• 3.3.3 Worker's decision . 60
• 3.4 Aggregate decision 64
• 3.4.1 Aggregation of individuals' decisions 64
• 3.4.2 Government expenditure, tax, and social insurance 68
• 3.5 Steady-state equilibrium . 70
• 3.6 Quantitative steady-state equilibrium 75
• 3.7 Sensitivity analysis 77
• 3.7.1 Effects of bequest intensity for workers and retirees 78
• 3.7.2 Effects of changes in Social Security benefits for retirees' dependents 83
• 3.7.3 Effects of Retiree Survival Rates on Insurance and Capital 86
• 3.8 Sub-conclusion 91
• 4 Conclusion 93
• A Appendix 96
• A.1 Proofs for Chapter 2 . 96
• A.1.1 Consumption propensity for retirees' keeping the health condition . 96
• A.1.2 Healthy or unhealthy retirees' valuation for social security and health insurance 98
• A.1.3 Declining health retirees consumption propensity . 100
• A.1.4 Declining health retirees valuation for social security and health insurance. 102
• A.1.5 Healthy worker's consumption propensity 103
• A.1.6 Healthy worker's risk-adjusted valuation 105
• A.1.7 Unhealthy worker's consumption propensity 108
• A.1.8 Unhealthy worker's risk-adjusted valuation . 110
• A.2 Proofs for Chapter 3 . 112
• A.2.1 Dependent's propensity to consume out of wealth . 112
• A.2.2 Dependent's valuation for Social Security benefits . 114
• A.2.3 Retiree's propensity to consume out of wealth . 115
• A.2.4 Retiree's valuation for Social Security benefits and life insurance 117
• A.2.5 Worker's propensity to consume out of wealth . 119
• A.2.6 Worker's insurance-adjusted valuation . 122