上田　路子

概要：Rises in suicide rates following media reports of the deaths by suicide of public figures are a well-documented phenomenon. However, it remains unclear why, or by what exact mechanism, celebrity suicides act to increase suicidal risk in the wider public due to the lack of data showing how the public understands and reacts to the suicide of well-known figures. This study used a supervised machine learning approach to investigate the emotional content of almost 1 million messages sent on Twitter related to the suicides of 18 prominent individuals in Japan between 2010 and 2014. The results revealed that different demographic characteristics of the deceased person (age, gender, and occupation) resulted in significant differences in emotional response; notably that the suicides of younger people, of women and of people in entertainment careers created more emotional responses (measured as a ratio of emotionally-coded tweets within the overall volume of tweets for each case) than for older people, men, and those in other careers. Moreover, certain types of emotional response were shown to correlate to subsequent rises in the national suicide counts, with “surprised” reactions being positively correlated with the suicide counts, while a high proportion of polite messages of condolence were negatively correlated. The study demonstrates the importance of, and describes a methodology for, considering the content of social media messages, not just their volume, in research into the mechanism by which these widely-reported deaths increase suicide risk in the broader public.

概要：Background: Previous research on hourly diurnal variation in suicide frequency has often suffered from geographical and time-span limitations in the data. We studied diurnal and daily variations of suicide by analyzing a large dataset based on the national death registry in Japan between 1974 and 2014. Methods: The diurnal and daily patterns of 873,268 suicide deaths over 41 years were examined by sex and age group through Poisson regression and visual inspection. We also investigated whether these patterns are related to Japan's economic conditions. Results: Suicide by middle-aged males was most frequent in the early morning especially on Mondays after the end of Japan's high growth period. We also observed large midnight peaks in suicides among young and middle-aged males. The proportion of early morning suicide deaths by young and middle-aged males increased as the country's unemployment rose. Females and elderly males were more likely to die by suicide during the day than at night. Limitation: Our study examined time of death, not time of suicide attempt. It is possible that there is a discrepancy between the two. Conclusions: Different subpopulations die by suicide at different times of the day and days of the week. Time patterns of suicide varied considerably over time, suggesting that they cannot be explained by biological circadian rhythm alone. Our findings suggest that the patterns are partly explained by economic conditions. Future suicide prevention efforts should consider the time patterns of suicide unique to each subpopulation, especially when economic growth is depressed.

ISSN：02779536

概要：© 2017 Elsevier Ltd A substantial amount of evidence indicates that news coverage of suicide deaths by celebrities is followed by an increase in suicide rates, suggesting a copycat behavior. However, the underlying process by which celebrity status and media coverage leads to increases in subsequent suicides is still unclear. This study collected over 1 million individual messages (“tweets”) posted on Twitter that were related to 26 prominent figures in Japan who died by suicide between 2010 and 2014 and investigated whether media reports on suicide deaths that generated a greater level of reactions by the public are likely to be followed by a larger increase in actual suicides. We also compared the number of Twitter posts and the number of media reports in newspaper and on television to understand whether the number of messages on Twitter in response to the deaths corresponds to the amount of coverage in the traditional media. Using daily data from Japan's national death registry between 2010 and 2014, our analysis found an increase in actual suicides only when suicide deaths generated a large reaction from Twitter users. In contrast, no discernible increase in suicide counts was observed when the analysis included suicide deaths to which Twitter users did not show much interest, even when these deaths were covered considerably by the traditional media. This study also found suicides by relatively young entertainers generated a large number of posts on Twitter. This sharply contrasts with the relatively smaller volume of reaction to them generated by traditional forms of media, which focuses more on the deaths of non-entertainers. The results of this study strongly suggest that it is not sufficient to examine only traditional news media when investigating the impact of media reports on actual suicides.

概要：© by De Gruyter 2016.What are the fiscal consequences of legislative term limits? To answer this question, we first develop a legislative bargaining model that describes negotiations over the allocation of distributive projects among legislators with different levels of seniority. Building on several predictions from the model, we develop two hypotheses for empirical testing. First, the adoption of term limits that results in a larger reduction in the variance of seniority within a legislature increases the amount of government spending. Second, legislatures that adopt stricter term limits increase the amount of government spending, while legislatures that adopt moderate term limits show no change in the amount. We provide evidence for these hypotheses using panel data for 49 US state legislatures between 1980 and 2010.

ISBN：978-981-10-1499-4

総ページ数：238ISBN：978-4641173910