"Suicide and Life Insurance"

In this paper, we investigate the nexus between life insurance and suicide behavior using OECD cross-country data from 1980 to 2002. Through semiparametric instrumental variable regressions with fixed effects, we find that for the majority of observations, there exists a positive relationship between suicide rate and life insurance density (premium per capita). Since life insurance policies pay death benefits even in suicide cases after the suicide exemption period, the presence of adverse selection and moral hazard suggests an incentive effect that leads to this positive relationship. The novelty of our analysis lies in the use of cross-country variations in the length of the suicide exemption period in life insurance policies as the identifying instrument for life insurance density. Our results provide compelling evidence suggesting the existence of adverse selection and moral hazards in life insurance markets in OECD countries.

"Joint Liability Borrowing and Suicide"

This paper shows that joint liability borrowing may put too much pressure on the borrower, mainly through the stigma in case of repayment failure, and leads to a vexing outcome|the suicide of the borrower. We provide a model of joint liability borrowing which facilitates credit market transaction ex ante but may induce suicides ex post in the bad state. We introduce some supportive evidence from a suicide survey in Japan.

"How Is Suicide Different in Japan?"

In this study, we analyze suicide rates among OECD countries with a particular effort made to gain insight into how suicide in Japan is different from suicides in other OECD countries. Several findings emerged from fixed effect panel regressions with country specific time-trend. First, the impacts of socioeconomic variables vary across different age-gender groups. Second, in general, better economic conditions such as high level of income and higher economic growth reduce suicide rate while income inequality increases suicide rate. Third, suicide rate is more sensitive to the economic factors captured by real GDP per capita, growth rate of real GDP per capita, and Gini index than to the social factors represented by divorce rate, birth rate, female labor participation rate, and alcohol consumption. Fourth, female and elderly generation suicides are more difficult to be accounted for. Finally, in accordance to the general belief, the suicide problem in Japan is very different from those of the other OECD countries. The impact of socioeconomic variables is greater in Japan than in other OECD countries. Moreover, the empirical result of significant Gini index in Japan is consistent with individuals' aversion to inequality and relative deprivation discussed in the recent literature.

Syntactic View of Sigma-Tau Generation of Permutations

We give a syntactic view of the Sawada-Williams $(\sigma,\tau)$-generation of permutations. The corresponding sequence of $\sigma-\tau$-operations, of length $n!-1$ is shown to be highly compressible: it has $O(n^2\log n)$ bit description. Using this compact description we design fast algorithms for ranking and unranking permutations.Comment: accepted on LATA201

"Those Who Are Left Behind: An Estimate of the Number of Family Members of Suicide Victims in Japan"

This paper contributes to the literature of suicide studies by presenting procedures and its estimates of the number of family members who lose their loved ones to suicide. Using Japanese aggregate level data, three main findings emerge: first, there are approximately five bereaved family members per suicide; second, in 2006, there were about 90,000 children who had lost a parent to suicide; and third, in 2006, there were about three million living family members who had lost a loved one to suicide. The direct production loss of bereaved family members in 2006 alone is estimated at approximately 197 million USD. These results are valuable in evaluating the cost-effectiveness of suicide prevention programs and in designing appropriate policy instruments.

Gray Codes and Symmetric Chains

We consider the problem of constructing a cyclic listing of all bitstrings of length 2n+1 with Hamming weights in the interval [n+1-l,n+l], where 1 = 12

"The Jump, Inertia, and Juvenization of Suicides in Japan"

This article investigates the abrupt jump in the number of suicide cases in Japan in 1998 and the subsequent persistency of this figure by utilizing a generalized decomposition formula. In particular, by considering the change in the demographic structure, we decompose the 1998 jump in the number of suicides and the cumulative changes from 1998 to 2007 by age and gender. Our results show that while the abrupt jump in the number of suicides in 1998 is mainly attributed to middleaged males, who are 40 to 59 years old, the consistently high number of suicides after 1998 is because of the suicides of people from the younger generation, i.e., the age group from 20 to 39 years. This "juvenization" in suicides is also reflected by the change in the means for committing suicide. Finally, aging is also identified as an impediment in combating the high suicide numbers.