Comment on “Aging Population, Retirement, and Risk Taking”

2020 ◽  
Vol 66 (6) ◽  
pp. 2787-2791 ◽  
Author(s):  
Moshe Levy
Keyword(s):  
Lower Bound ◽  
Risk Taking ◽  
Marginal Utility ◽  
Geometric Mean ◽  
Aging Population ◽  
Economic Implication ◽  
Investment Horizon ◽  
Geometric Means ◽  
Economic Implications ◽  
Long Run

Levy [Levy H (2016) Aging population, retirement, and risk taking. Management Sci. 62(5):1415–1430] argues that the portfolio with the maximal geometric mean (MGM) asymptotically dominates any other portfolio; that is, as the investment horizon becomes very long, the MGM portfolio is preferred over any other portfolio for all preferences with marginal utility bounded from above, [Formula: see text]. The important economic implication is that in the long run, an all-equity portfolio dominates bond (or mixed) portfolios, which have lower geometric means. This comment shows that Levy’s result holds only if the marginal utility is also bounded from below. This seemingly technical correction has profound economic implications, because many commonly accepted preferences do not satisfy the lower bound condition. Indeed, for some standard preferences, the optimal stock–bond mix shifts toward bonds, not stocks, as the horizon increases, exactly opposite to Levy’s conclusion. This paper was accepted by Gustavo Manso, finance.

Aging Population, Retirement, and Risk Taking: Reply

2020 ◽  
Vol 66 (6) ◽  
pp. 2796-2799
Author(s):  
Haim Levy
Keyword(s):  
Empirical Evidence ◽  
Risk Taking ◽  
Geometric Mean ◽  
Aging Population ◽  
The Other ◽  
Investment Horizon ◽  
Technical Error ◽  
Long Run ◽  
Original Theorem

In theorem 1 given in my paper, “Aging Population, Retirement, and Risk Taking” [Levy H (2016a) Aging population, retirement, and risk taking. Management Sci. 62(5):1415–1430.], there is indeed a technical error. Yet, adding one condition to the theorem (which can be added in two alternate ways) is sufficient to ensure the dominance of stocks over bonds in the very long run. For the commonly employed preferences, the empirical evidence conforms with the claim given in my original theorem 1, asserting that the portfolio with the higher geometric mean (stocks) dominates the other portfolio under consideration (bonds) as the investment horizon increases indefinitely. Thus, as advocated in my paper, stocks dominate bonds for investors with typical preferences who save for retirement. This paper was accepted by Karl Deither, finance.

Comment on “Aging Population, Retirement, and Risk Taking”

2020 ◽  
Vol 66 (6) ◽  
pp. 2792-2795 ◽  
Author(s):  
Rachel J. Huang ◽  
Larry Y. Tzeng ◽  
Jr-Yan Wang ◽  
Lin Zhao
Keyword(s):  
Risk Taking ◽  
Stochastic Dominance ◽  
Marginal Utility ◽  
Aging Population ◽  
Decision Makers ◽  
Terminal Wealth ◽  
Ranking Criterion ◽  
Log Normal ◽  
Necessary And Sufficient ◽  
Log Normal Distribution

Levy [Levy H (2016) Aging population, retirement, and risk taking. Management Sci. 62(5):1415–1430.] proposes asymptotic first-degree stochastic dominance (AFSD) as a distribution-ranking criterion for all nonsatiable decision makers with infinite investment horizons. By assuming that the terminal wealth follows a log-normal distribution and that the marginal utility is bounded, he offers the necessary and sufficient distributional condition for AFSD. Given Levy’s setting, we provide a counterexample to show that his condition is not necessary and offer the correct equivalent distributional condition for AFSD. This paper was accepted by Karl Diether, finance.

scholarly journals Pharmacokinetic Interactions between the Hormonal Emergency Contraception, Levonorgestrel (Plan B), and Efavirenz

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Monica L. Carten ◽  
Jennifer J. Kiser ◽  
Awewura Kwara ◽  
Samantha Mawhinney ◽  
Susan Cu-Uvin
Keyword(s):  
Geometric Mean ◽  
Liver Function Tests ◽  
Open Label ◽  
Time Curve ◽  
Geometric Means ◽  
Concentration Time ◽  
Plan B ◽  
Effective Contraception ◽  
Grade 3 ◽  
Hiv Negative

Objectives. Compare the Plan B levonorgestrel (LNG) area under the concentration- time curve (AUC12) prior to and with efavirenz (EFV).Design. Prospective, open-label, single-arm, equivalence study.Methods. Healthy HIV-negative subjects underwent 12 hr intensive pharmacokinetic (PK) sampling following single dose LNG alone and after 14 days of EFV. Geometric means, Geometric Mean Ratios, and 90% confidence intervals (CI) are reported for PK Parameters.T-tests were utilized. Clinical parameters and liver function tests (LFTs) were assessed.Results. 24 women enrolled and 21 completed the study. With EFV, LNG AUC12was reduced 56% (95% CI: 49%, 62%) from 42.9 to 17.8 ng*hr/mL, and maximum concentration (Cmax⁡) was reduced 41% (95% CI: 33%, 50%) from 8.4 to 4.6 ng/mL. LNG was well tolerated with no grade 3 or 4 treatment-related toxicities.Conclusions. EFV significantly reduced LNG exposures. Higher LNG doses may be required with EFV. These results reinforce the importance of effective contraception in women taking EFV.

scholarly journals Analyzing Dependent Variables with Multiple Surrogates in Accounting Research

2018 ◽  
Author(s):  
Enyi Enyi
Keyword(s):  
Logistic Regression ◽  
Regression Analysis ◽  
Performance Studies ◽  
Geometric Mean ◽  
A Priori ◽  
Geometric Means ◽  
Canonical Correlations ◽  
Dependent Variables ◽  
Actual Outcome ◽  
Ethical Clearance

The paper contains details a research carried out to show that the use of geometric mean to unify multivariate dependent variables in financial performance studies gives better and more practical results than the multiple abstraction analysis provided using advanced econometric tools such as TLS, PLS, MCA, Canonical correlations etc.<div>The study used the logistic regression analysis to compare the a priori expectations of 30 Ph.D research theses with their actual outcomes using econometric tools and the actual outcome using geometric means. The study used Ph.D theses in accounting and finance sourced from the libraries of four universities in Nigeria.</div><div>The study was a desktop research using publicly available literary resources and as such requires no ethical clearance.</div>

scholarly journals Recognition of International Education in Japanese Teachers

2017 ◽  
Vol 5 (2) ◽  
pp. 53 ◽  
Author(s):  
Masami Yoshida
Keyword(s):  
International Education ◽  
School Environment ◽  
Geometric Mean ◽  
Intercultural Education ◽  
Multiple Comparison ◽  
Geometric Means ◽  
Suburban Areas ◽  
The Third ◽  
Questionnaire Method ◽  
Multiple Comparison Procedures

Education for international understanding in Japan was focused to develop its own national identity as well as to recognize its coexistence through intercultural education. Then, we have investigated the opinions of Japanese school teachers in terms of their recognition of the necessary content to introduce school instruction of intercultural education using a questionnaire method. In the questionnaire, 14 items of three principles were extracted from the criteria of UNESCO (United Nations Educational, Scientific, and Cultural Organization). For analyzing the collected data, the geometric mean was used. Subsequently, a one-way ANOVA test and multiple-comparison procedures were conducted. By including teachers in suburban areas in Japan, we obtained 123 valid responses. All items showed a necessary level of geometric means, and particularly items of the first principle “respect cultural identity” and items of the second principle “provide knowledge for participation” showed statistically significant positive necessity levels. However, an answer of “I have never thought” increased in the third principle “provide a chance to contribute” that was closely related to present world concern of global citizenship education and statistically was not significant. From the result of the multiple-comparison procedures of the second principle and the third principle, seven pairs of statistically different items were extracted. Then, we discussed the enhancement between Japan and UNESCO and influence of school environment in Japan.

scholarly journals Resolving New Keynesian Anomalies with Wealth in the Utility Function

2019 ◽  
pp. 1-46 ◽  
Author(s):  
Pascal Michaillat ◽  
Emmanuel Saez
Keyword(s):  
Lower Bound ◽  
Utility Function ◽  
Social Status ◽  
Government Spending ◽  
Marginal Utility ◽  
New Keynesian ◽  
Zero Lower Bound ◽  
Forward Guidance ◽  
Keynesian Model ◽  
Low Levels

At the zero lower bound, the New Keynesian model predicts that output and inflation collapse to implausibly low levels, and that government spending and forward guidance have implausibly large effects. To resolve these anomalies, we introduce wealth into the utility function; the justification is that wealth is a marker of social status, and people value status. Since people partly save to accrue social status, the Euler equation is modified. As a result, when the marginal utility of wealth is sufficiently large, the dynamical system representing the zero-lower-bound equilibrium transforms from a saddle to a source—which resolves all the anomalies.

scholarly journals A Comparison of the Arithmetic and Geometric Means in Estimating Stump Diameter, Basal Area, and Volume in Appalachian Hardwoods

2007 ◽  
Vol 24 (1) ◽  
pp. 71-73 ◽  
Author(s):  
Harry V. Wiant ◽  
John R. Brooks
Keyword(s):  
Geometric Mean ◽  
Basal Area ◽  
Cross Sectional Area ◽  
Practical Significance ◽  
Sectional Area ◽  
Cross Sectional ◽  
Geometric Means ◽  
The Difference ◽  
Appalachian Hardwoods ◽  
Stump Diameter

Abstract The difference between the use of the arithmetic and geometric means for estimation of average stump diameter, stump cross-sectional area and estimated tree volume was investigated using measurements from 739 stumps from an Appalachian hardwood stand located in central West Virginia. Although average stump diameter, cross-sectional area, and tree volumes were statistically different between estimates based on the arithmetic and geometric mean diameter, these differences were of little practical significance. The difference in average stem diameter, cross-sectional area, tree cubic volume, and board foot volume were 0.05 in, 0.01 ft2, 0.45 ft3, and 2.41 bd ft, respectively.

scholarly journals Tobacco-Specific Nitrosamines (NNAL, NNN, NAT, and NAB) Exposures in the US Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013–2014)

2020 ◽  
Author(s):  
Baoyun Xia ◽  
Benjamin C Blount ◽  
Tonya Guillot ◽  
Christina Brosius ◽  
Yao Li ◽  
...  
Keyword(s):  
Solid Phase ◽  
Geometric Mean ◽  
Tobacco Product ◽  
Geometric Means ◽  
Population Assessment ◽  
Frequency Of Use ◽  
The Us ◽  
Liquid Chromatography Tandem Mass ◽  
Highly Correlated ◽  
Tobacco Specific Nitrosamines

Abstract Introduction The tobacco-specific nitrosamines (TSNAs) are an important group of carcinogens found in tobacco and tobacco smoke. To describe and characterize the levels of TSNAs in the Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013–2014), we present four biomarkers of TSNA exposure: N′-nitrosonornicotine, N′-nitrosoanabasine, N′-nitrosoanatabine, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) which is the primary urinary metabolite of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone. Methods We measured total TSNAs in 11 522 adults who provided urine using automated solid-phase extraction coupled to isotope dilution liquid chromatography–tandem mass spectrometry. After exclusions in this current analysis, we selected 11 004 NNAL results, 10 753 N′-nitrosonornicotine results, 10 919 N′-nitrosoanatabine results, and 10 996 N′-nitrosoanabasine results for data analysis. Geometric means and correlations were calculated using SAS and SUDAAN. Results TSNA concentrations were associated with choice of tobacco product and frequency of use. Among established, every day, exclusive tobacco product users, the geometric mean urinary NNAL concentration was highest for smokeless tobacco users (993.3; 95% confidence interval [CI: 839.2, 1147.3] ng/g creatinine), followed by all types of combustible tobacco product users (285.4; 95% CI: [267.9, 303.0] ng/g creatinine), poly tobacco users (278.6; 95% CI: [254.9, 302.2] ng/g creatinine), and e-cigarette product users (6.3; 95% CI: [4.7, 7.9] ng/g creatinine). TSNA concentrations were higher in every day users than in intermittent users for all the tobacco product groups. Among single product users, exposure to TSNAs differed by sex, age, race/ethnicity, and education. Urinary TSNAs and nicotine metabolite biomarkers were also highly correlated. Conclusions We have provided PATH Study estimates of TSNA exposure among US adult users of a variety of tobacco products. These data can inform future tobacco product and human exposure evaluations and related regulatory activities.

scholarly journals Retrospection of Anti–Blood Group Antibody Proficiency Testing Data Using the Geometric Mean and Standard Deviation

2019 ◽  
Vol 153 (4) ◽  
pp. 530-536 ◽  
Author(s):  
John Jeongseok Yang ◽  
Yousun Chung ◽  
Hyungsuk Kim ◽  
Dae-Hyun Ko ◽  
Sang-Hyun Hwang ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Blood Group ◽  
Proficiency Testing ◽  
Geometric Mean ◽  
Geometric Standard Deviation ◽  
Geometric Means ◽  
Consensus Criterion ◽  
Mode 2 ◽  
Testing Data ◽  
The Mean

Abstract Objectives We reanalyzed the data from proficiency testing (PT) to assess the effect of the geometric mean in the statistical analysis of immunohematologic data. Methods Using the five most recent anti–blood group antibody titer participant summary results, the geometric mean (GM) ±2 × geometric standard deviation (GSD) was used as the comparative consensus criterion to mode ±2 titers. Results Using the PT evaluation criterion of mode ±2 titers, the mean percentages of participants with acceptable results were 97.5% and 97.8% for anti-A and anti-D, respectively. When applying GM ±2 GSD, the mean percentages of acceptable results were 96.1% (anti-A) and 96.1% (anti-D). The percentages of responses included in each consensus criterion were lower using GM ±2 GSD, with a few exceptions. Conclusions Geometric means are more robust and precise in visualizing the central tendency. This method can improve the statistical robustness of PT evaluations.

scholarly journals Global Economic Meltdown: Greenspan�s Legacy

2009 ◽  
Vol 34 (3) ◽  
pp. 9-14 ◽  
Author(s):  
Samir K Barua ◽  
Mahendra R Gujarathi
Keyword(s):  
Risk Taking ◽  
World Economy ◽  
Fair Value ◽  
Fair Value Accounting ◽  
Cautionary Note ◽  
Monetary Expansion ◽  
The Great Depression ◽  
Long Run ◽  
The World ◽  
Insight Into

In the event of statedly the deepest global crisis ever since the Great Depression, with the world economy mired in a severe economic meltdown, Samir K Barua and Mahendra R Gujarathi identify the factors and the players that incubated and nurtured the meltdown. The policies of deregulation, monetary expansion, and fair value accounting are specifically addressed in a historical perspective. The authors offer an insight into how sequentially the lawmakers first created the potent environment for risk-taking through unrestrained deregulation, the Federal Reserve then set the stage for the crisis with a policy of unbridled monetary expansion, and the accounting standardsetter finally relaxed norms to provide support for hiding the losses incurred� thus together fuelling the crisis. Although several trillions of dollars have been pumped into the market to maintain the credit flow, it is yet uncertain as to how the crisis will impact in the long run, the authors conclude on a cautionary note.

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