Optimal Investment Strategy to Minimize the Probability of Lifetime Ruin

Abstract

I study the problem of how individuals should invest their wealth in a risky financial market to minimize the probability that they outlive their wealth, also known as the probability of lifetime ruin. Specifically, I determine the optimal investment strategy of an individual who targets a given rate of consumption and seeks to minimize the probability of lifetime ruin. Two forms of the consumption function are considered: (1) The individual consumes at a constant (real) dollar rate, and (2) the individual consumes a constant proportion of his or her wealth. The first is arguably more realistic, but the second has a close connection with optimal consumption in Merton’s model of optimal consumption and investment under power utility.

For constant force of mortality, I determine (a) the probability that individuals outlive their wealth if they follow the optimal investment strategy; (b) the corresponding optimal investment rule that tells individuals how much money to invest in the risky asset for a given wealth level; (c) comparative statics for the functions in (a) and (b); (d) the distribution of the time of lifetime ruin, given that ruin occurs; and (e) the distribution of bequest, given that ruin does not occur. I also include numerical examples to illustrate how the formulas developed in this paper might be applied.     

On dynamic spectral risk measures,a limit theorem and optimal portfolio allocation

In this paper, we propose the notion of continuous-time dynamic spectral risk measure (DSR). Adopting a Poisson random measure setting, we define this class of dynamic coherent risk measures in terms of certain backward stochastic differential equations. By establishing a functional limit theorem, we show that DSRs may be considered to be (strongly) time-consistent continuous-time extensions of iterated spectral risk measures, which are obtained by iterating a given spectral risk measure (such as expected shortfall) along a given time-grid. Specifically, we demonstrate that any DSR arises in the limit of a sequence of such iterated spectral risk measures driven by lattice random walks, under suitable scaling and vanishing temporal and spatial mesh sizes. To illustrate its use in financial optimisation problems, we analyse a dynamic portfolio optimisation problem under a DSR.     

Seasonal and Spatial Variations in Demand for and Elasticities of Fish Products in the United States: An Analysis Based on Market‐Level Scanner Data

Seasonally and spatially varying demand elasticities would provide important information to seafood producers and marketers as well as policy makers. We analyzed the effects of season and space on (i) demand (translation effects) and (ii) price as well as expenditure elasticities of demand (scaling effects) for 13 finfish species in the United States. The paper used market‐level scanner data for 52 U.S. markets. Results suggest that not only the quantity demanded, but also the demand elasticities vary across species, seasons, and geography; not only does the degree of competition among finfish products vary considerably over space, but substituting products themselves change. These results highlight the importance of studying consumer demand behavior at species level, across seasons and geography, particularly as it sheds important light on some important policy issues such as the potential substitution between catfish and tilapia in the U.S. markets.     

Training design enhancement through training evaluation: Effects on training transfer

This research investigates the linkage between training evaluation, learning design and training transfer. A new training evaluation model, (i.e., learning-transfer evaluation model [LTEM]), was used to examine its ability to provide evaluative evidence through robust assessments in pre-, post- and delayed assessments. The model was used to improve the training design of a nursing training programme and to nudge the stakeholders to change their training practices. A mixed-methods research approach, called convergent parallel, was employed to study the influence of the LTEM model in training design improvement by assessing the perceptions of nurse trainees, trainers and a nurse educator towards the instructional design of the training programme. A quantitative approach was used to examine the extent to which the improved programme using an iterative design cycle would result in improved performance among four groups (i.e., one baseline and three treatment groups). The integrated data showed that the LTEM model influenced the stakeholders to focus more on skills practice. With this shift of mindset, the training design was enhanced based on the principles of learning design, cognitive science and multimedia principles. Results of the pre-, post- and delayed posttests showed higher mean scores in the three treatment groups compared to the baseline group. For the measure of transfer, while the treatment groups scored higher, there was no statistically significant difference among all four groups. This could be attributed to nurses’ varied levels of experience, negative transfer and the use of different evaluation matrices in the study and by the hospital.     

Two sided efficient frontiers at multiple time horizons

Annals of Finance - Two price economy principles motivate measuring risk by the cost of acquiring the opposite of the centered or pure risk position at its upper price. Asymmetry in returns leads...     

Measuring learning from others: The development and validation of the Proactive Social Informal Learning Questionnaire

The present study aims to develop, validate, and cross-validate an instrument measuring three proactive social informal learning activities, namely feedback seeking, help seeking and information seeking. Prior research mainly focused on detecting or measuring the frequency of these seeking behaviours and did not consider whether the information, help or feedback that has been sought was also used. Furthermore, although these seeking behaviours were studied extensively in different research fields, the current study takes a learning perspective and interprets feedback, help and information seeking as learning activities. The questionnaire was completed by a convenient sample of 650 professionals working in higher education, consultancy, retail and food production. We performed an exploratory factor analysis (N = 230 educators) to explore the structure of the questionnaire. This was followed by a confirmatory factor analysis (N = 230 educators) to confirm the structure. Finally, we cross-validated the questionnaire in a sample of business professionals (N = 190) by testing for measurement invariance. The final questionnaire resulted in a five-factor structure measuring the (1) Use of Feedback Seeking, (2) Frequency of Help and Information Seeking, (3) Use of Help seeking, (4) Use of Information Seeking and (5) Frequency of Feedback Seeking. The current study presents a preliminary, yet promising instrument that taps into proactive social informal learning.     

The value of informal learning within work-based learning: The economic benefits of WBL

Recent updates to federal policy governing career and technical education (CTE) in the United States have emphasised the need to include work-based learning (WBL) experiences as central components of CTE programming. Many of these experiences showcase an informal learning component which has strong ties to early career success as suggested by the Human Capital Theory. This study explores the following questions: What is the relationship between WBL and early career income? Are there differential relationships based on the type of WBL experience? The Education Longitudinal Study of 2002 (ELS) includes nationally representative data for student participation in WBL and early career income. We used school-fixed effects and propensity score matching techniques to respond to our questions regarding the potential relationship between WBL participation and early career income. We found that students who participated in at least one WBL experience in high school could expect to have an average 7% higher income compared to non-WBL participants. With respect to specific WBL experiences, job shadowing, community service, and mentoring had the largest positive relationship to higher early career income. Findings from this study indicate that participation in WBL experiences can have a positive impact on a high school graduate's college and career readiness as measured through early career income. Given the differential relationships observed for different types of WBL, schools, policymakers, and students should explore WBL options that best align with their personal goals.