本研究主要以Cox 迴歸模型為主軸，以1995年7月1日至1999年5月7日公務人員退撫基金成員:公務人員及教育人員為研究對象，分析影響基金成員各項脫退的個別變數，並量化所擇取之變數的影響，以估計各個基金成員的脫退率。同時針對現有基金成員，評估退撫基金短期現金支出並分析之。實證結果發現：藉由Cox迴歸模型之分析可知，相異的脫退因素，被不同的迴歸變數所影響著，且各個變數對各項脫退的影響程度亦存在著差異。短期現金支出的評估結果顯示，各項給付支出，以退休給付的支出佔最大的比例，次為資遣、死亡及離職給付。而人數比例較少的教育人員，其脫退給付支出金額，高於公務人員之給付支出。 略 / Cox regression model is proposed in this study to investigate the demographic factors (i.e., gender, age, seniority, salary scale and the entry date) that influence the turnover pattern of the plan members. This research has focused on the government employees and public school teachers in Taiwan Public Employees Retirement System (Tai-PERS). Quantitative analyses on turnover are performed through monitoring and selecting the significant factors in Cox regression model. Finally based on the current members in Tai-PERS, the short-term cash outflow is projected. Based on the empirical results, different causes of turnover (i.e., death, withdrawal, layoff and retirernent) are influenced by the selected factors. Significant differences have been found within the various causes of decrements. Result from the short-term cash outflow shows that the payment due to retirement has the largest proportion. Then follows the payment amount due to payoff, death and withdrawal if we rank them in order. In additions, the total payments of the public school teachers are larger than those of the government employees, while the plan members of the public school teachers are comparatively less.

本論文應用數學規劃建立符合我國法令規範與投資政策說明書之投資政策及風險管理的資產負債管理模型。主要的討論對象為國民年金、公務人員退休撫卹基金與新制勞工退休金。模型中主要透過資產配置的收益與提撥收入維持現金流的平衡，以支應現在或未來的負債。在提出的模型中，採取維持最低基金公積率的策略，以確保長期的償付能力。當償付能力不足時，以政府撥補或是修正提撥率處理巨額的虧損。且使用機率限制式將發生不足的風險控制在可接受的範圍內。因此本論文提出的模型為多階段的有補償的混和整數隨機規劃模型。

針對各國普遍面臨人口結構逐漸老化、退休人口增加問題，世界銀行曾提出應建立至少三層保障的養老制度之呼籲；而我國迄今尚未建構出一套全面性之老年經濟生活安全保障制度，現有退休制度係依國民職業身分作為區分基礎。近幾年政府財政日趨惡化，加以國內經濟景氣不佳，失業率節節升高，公務人員由於工作與薪資相對較為穩定，其退休給付亦較完備；因此，遂引起各界對公務人員退休給付及其條件之合理及公平性的諸多討論。而公務人員退撫基金管理良窳，除攸關公務人員退休權益，亦牽涉政府最後給付責任，在政府可用資源相對減少下，如何防範政治力介入，暨因應現有制度與管理上的若干缺失，避免未來發生嚴重財務危機，均為本研究之重點。 本研究採取文獻探討、比較研究法，並輔以德菲爾法（Delphi Method）、問卷調查等方法，就公平及管理角度檢視現行公務人員退休制度所存在之缺失及具體改進之道。研究結果發現大多數受訪者認為我國對老年經濟生活安全之保障，與個人從事職業別有很大關聯；除軍公教人員以外之其他職域與非工資勞動者的老年經濟生活保障普遍不足，故在制度比較上常衍生出差別性待遇公平性問題；而退撫基金經營決策又常有政治力介入，特別是政經情勢不穩定時，除非逐漸民營化，政府僅擔任監督者角色，否則既使修法明定政府干預、挪用基金等限制條文，只要仍維持現行制度精神，由政府管理，便很難防範政治力介入該基金之實際運作。 基此，本研究提出下述幾點建議：1.政府應致力提升其他職域（身分）人員之老年經濟生活安全保障；2.公務人員請領月退休金年齡條件應予以延後，並適度降低現行給付水準；3.研議增訂彈性退休規定，並研酌展期年金及減額年金之可行性；4.宜朝向「確定給付制」兼採「確定提撥制」混合制方向發展，並逐步提高「確定提撥制」比例及採個人退休金帳戶制；5.修法明確規範退撫基金提撥率之調整機制，以健全基金財務結構；6.宜逐步增加退撫基金國外投資配置比例；7.應研酌未達法定最低收益由國庫補足差額之規定，以免否對資產長期配置造成扭曲；8.對於有價證券之投資應改採市價法評價，以反映基金資產真實價值；9.加強退撫基金財務資訊公開，以利全體投保人之監督；10.現行基金管理與監理組織，可研酌精簡合併為一獨立專業監理機關。11.修法使退撫基金經營管理趨向私有化與自由化。 / To confront the ever growing ageing trend and consequent retirement tide, the World Bank has contended three pillars of old age security over the past few years. The ROC government, however, has not yet launched a national pension scheme to ensure the elderly economic security so far although the Plan has been worked out for some time. The country is currently adopting a retirement system based on people’s occupation. Civil servants all along enjoy relatively sound and stabilized retirement benefits even under the aggravating financial difficulties and the economy recession. Together with the increasing unemployment rate, this phenomenon has augmented a great deal of discussion with regard to its fairness. In addition, since the government has played significant role in terms of Pension Fund Management, how to prevent political intervention and avoid mismanagement particularly during economic crisis certainly deserve close scrutiny. In light of the aforementioned, this study, based on literature review, survey, and Delphi, focuses on the fairness and management perspectives of the existing pension system for civil servants. It is found that most interviewees agree that civil servants comparatively enjoy better retirement benefits than the rest of the population since the current pension system has been designed on occupational basis. It is further observed by the interviewees that political intervention does exist in terms of Pension Fund Management especially during economic recession. It is thus harbored that perhaps only through “privatization”, such intervention can come to its stop. The study, among other things, suggests the followings: 1.A national pension scheme covering all people is required. 2.Postponing the age of receiving annuity from the current 50 to a later age and reasonably cutting off some civil servants’ pension benefits need to be addressed. 3.Adding flexibility to current civil servants’ retirement system is worth pondering. 4.Working out a system blending together “defined benefit” and “defined contribution” in which the proportion of “defined contribution” should be gradually enlarged. Thoughts with regard to “individual account” should also be studied. 5.Adjusting the insurance fee for pension fund is necessary in order to ensure financial viability. 6.Bigger proportion of pension funds’ overseas investment should be allowed. 7.Investment in securities should be evaluated with market price to reflect the actual value of fund assets. 8.Pension funds management report should be released to the general public for supervision. 9.Professional pension fund supervision mechanism has to be established. 10.Law provisions as to privatize and liberalize the pension fund need to be worked out.

本研究以確定給付型退休基金為對象，建構廣義隨機評價模型，以衡量不確定情況下退休基金之財務風險。希望藉著模型建構的過程，適切地描述基金評價過程中所應考量的各項要素。 為了強調基金評價時同時考量內外部精算假設的重要性，本研究將模型分為存活函數、經濟函數和給付函數三部份討論；存活函數利用離散時間非同質性半馬可夫過程（Discrete Time Non-Homogeneous semi-Markov Process）描述成員狀態轉移的機率，把成員工作年資、年齡和及狀態納入評價過程，有別於傳統僅以年齡為假設基礎之精算方法；經濟函數則以隨機過程表達外部環境的不確定性，結合上述假設資訊預估未來給付後，成為半馬可夫隨機精算評價模型，此一般性的模型能推展至基金評價時所需的各項流程。因此，本研究將模型應用於我國公務人員退撫基金，針對公務人員退撫基金的給付特性發展財務評價公式，完整地描述基金精算成本計算、未來人力與現金流量結構模擬以及敏感度分析等過程。 最後，本研究撰寫公務人員精算評價資訊系統，具體化半馬可夫隨機精算評價模型，實證公務人員退撫基金財務評價公式。實證結果也顯示，不論基金的性質或外部經濟環境，都將影響退休基金財務評價結果，為基金評價時不可忽略的精算假設。 / This study focuses on constructing a generalized valuation model for the defined benefit pension schemes. Financial soundness and funding stability are critical issues in pension fund management. In this study, a realistic stochastic model is built to monitor the uncertainty factors in affecting the financial risk and cash flow dynamics along the decision process. In order to evaluate the importance of the interior and exterior actuarial assumptions in pension valuation. Detailed models in describing the turnover patterns, economic uncertainties and benefit structures are explored. Semi-Markov process proposed by Dominicis, Manca and Granata (1991) and Janssen and Manca (1997) is extended in structuring the transition pattern of the plan’s population and the economic based factors are generated through stochastic processes. Modifications according to classification and movements of the plan member and the plan’s turnover pattern are employed to improve its practical usefulness. Then the actuarial valuations, cash flow analyses and workforce projection are performed and investigated. We has explicitly formulated the plan’s realistic phenomenon and implemented the proposed mechanism into a risk management framework for pension finance. By using this realistic approach, the cost factors could be monitored throughout the valuation. Typically these analyses involve substantial assumptions. This article has outlined the procedure of building the proposed model. Finally, Taiwan Public Employees Retirement System is simplified to illustrate the proposed methodology in pension valuation. The results from this study show that the structure of the pension schemes and the assumed economic factors are the significant factors in pension valuation. It also indicated that the fund manager can evaluate these impacts through the proposed model.

我國勞工退休金新制自2005年7月1日開始實施，由過去的確定給付制改為具有確定提撥特色的「個人帳戶制」。對於勞工而言，確定提撥制和過去確定給付制不同之處在於承擔退休金投資風險的責任將由雇主轉由個人承擔。如何透過退休機制的設計以降低退休金的投資風險是近年來的重要議題，因此本文主要從個人偏好與風險的觀點探討保證投資收益率制度與制度轉換選擇權等兩個降低確定提撥制投資風險的重要配套措施。 在本論文的第一篇研究中發現，資產配置與國際投資對保證成本的影響頗大，在個人可選擇資產配置的情況下，高投資風險的資產選擇將造成政府未來龐大的或有負債。為了解決政府保證成本過高造成代內與代間的財富移轉，本文從使用者付費與個人效用的觀點探討保證投資收益率制度的設計，發現藉由設立保證投資收益上限可提升風險趨避者、損失趨避者與後悔趨避者等偏好下的預期效用，且能降低個人管理下方風險所需的提撥成本與退休計畫參加者所需繳交的保證費用，故建議政府可將投資收益率上限納入保證投資收益率制度，供退休計畫參加者選擇合於本身偏好的保證收益率上限。 在近來許多國家的公、民營退休體系由過去以確定給付制改為確定提撥制，為了降低在確定提撥制下的退休金投資風險，在美國的佛羅里達州之公務人員退休體系中，存在著可供個人選擇是否轉換到確定給付制的機制。在我國勞退新制中除了從過去的確定給付制改為確定提撥制外，亦輔以「年金保險制」供勞工選擇與轉換，若年金保險制具有確定給付制的特徵，則勞工等於是擁有一個從確定提撥轉換轉到確定給付制的選擇權，因此制度選擇權的探討對我國而言亦是相當地重要。在本論文的第二篇研究中發現，當風險趨避程度越高則轉換至確定給付制的機率越高，轉換到確定給付制的高峰期會出現在開始工作的初期與屆臨退休之際等兩段期間。隨著工作期間的延長，個人轉換到確定給付制的機率越低，但仍可有效地提升退休金的所得替代率與達到降低退休金下方風險的效果，在加入退休制度初期不得轉換的限制之後，會降低轉換到確定給付制的機率。 / The Labor Retirement Pension Act enacted in 2005 introduced defined contribution (DC) pension plan for substituting the traditional defined benefit (DB) pension plan. In the defined contribution pension plan, the investment risk is transferred to the participants. However, the design of rate of return guarantee makes the investment risk less severe for participants. In the first essay, we find that the asset allocation and foreign investment have large impact on the guarantee cost: the high risky investment may result in large potential liability of the government in the future if participants have the investment portfolio choice. This study develops a framework to analyze design of rate of return guarantee from the financial engineering and user paid principle view. We find that the cap of investment return guarantee not only increases the expected utility of risk aversion, loss aversion and regret aversion, but also decreases the contribution cost to participant associated with managing the downside risk. Around the world, the defined contribution (DC) plans have been the primary trend of pension reform in the both public and private sector. In an attempt to decrease the investment risk associated with DC plan, the public employees are provided with an option to buy back DB plan in the Florida State of U.S.A. In the second essay, we find that the higher level of risk aversion is, the higher probability to buy back DB plan is. During the employee’s early years of service and as the employees near retirement, the probability to exercise the option is the highest. The probability to exercise the option is decreasing with the years of service being increasing; the option also increase the pension replacement rate as well as decrease the downside risk of pension. The probability to exercise the option is lower, when the option to buy back the DB plan is prohibited during the employee’s early years of service.