Variations in Age-Specific Homicide Death Rates: A Cohort Explanation for Changes in the Age Distribution of Homicide Deaths

27 pagesAn age-period-cohort characteristic model previously used to explain age-period-specific rates of homicide arrests for those 15 to 49 from 1960 to 1995 is applied to measures of age-period-specific homicide deaths. The extension of this model to the examination of homicide victimization is significant because we are able to test the utility of the model across a longer time span (1930 to 1995) and a wider range of ages (10 to 79) and disaggregated by sex and race (Whites and non-Whites). Although the results indicate that past and recent shifts in age-period-specific rates of homicide deaths are associated with specific characteristics of cohorts, there are some important differences across race and sex groupings in the effects of these characteristics. The effects of the cohort variables examined in our model are independent of age and period, often substantively large, and last throughout the life course. The results are consistent with Durkheimian explanations of lethal violence, hypotheses from victimization theory, and basic tenets of cohort theory

Cohort Variations and Changes in Age-Specific Suicide Rates over Time: Explaining Variations in Youth Suicide

38 pagesDramatic changes in the age distribution of suicide in the U.S. are associated with variations in the demographic characteristics of birth cohorts. Using an age-period-cohort-characteristic model, we show that cohort characteristics theoretically linked to integration and regulation have substantively strong and statistically significant relationships with changes in age-specific suicide rates from 1930 to 1995. Members of relatively large cohorts and of cohorts with higher percentages of nonmarital births are at greater risk for suicide throughout their life spans. These results appear for the total population and for race-sex subgroups, even though the age distributions of suicide differ substantially across these demographic groups. They can account for recent sharp increases in youth suicide, as well as more moderate increases in earlier decades

The Cohort-Size Sample-Size Conundrum: An Empirical Analysis and Assessment Using Homicide Arrest Data from 1960 to 1999

32 pagesA number of studies use the Age–Period–Cohort Characteristic (APCC) model to address the impact of cohort related factors on the age distribution of homicide offending. Several of these studies treat birth cohorts as spanning several years, an operationalization that most closely matches tenets of cohort theory, yet sharply reduces the number of observations available for analysis. Other studies define birth cohorts as those born within a single year, an operationalization that is theoretically problematic, but provides many more observations for analysis. We address the sample size problem by applying a time-series-cross-section model (panel model) with age-period-specific homicide arrest data from the United States for each year from 1960 to 1999, while operationalizing cohorts as five-year birth cohorts. Our panel model produces results that are very similar to those obtained from traditional multiyear APCC models. Substantively, the results provide a replication of work showing the importance of relative cohort size and cohort variations in family structure for explaining variations in age-period-specific homicide rates. The additional observations provided by our approach allow us to examine these relationships over time, and we find substantively important changes. The year-by-year estimates of the age distribution of homicide offending help us to examine the model during the epidemic of youth homicide

A Common Explanation for the Changing Age Distributions of Suicide and Homicide in the United States, 1930 to 2000

19 pagesA longstanding debate focuses on whether suicide and homicide rates walk hand in hand or whether they are reciprocally related. Much of the research on this issue investigates whether suicide or homicide predominates in certain geographic areas or whether they trend together over time. We theorize that the degree of social integration and social regulation associated with birth cohorts is negatively related to both of these forms of lethal violence.We develop a common explanation for shifts in the age distributions of homicide and suicide in the United States from 1930 to 2000. In this context, suicide rates and homicide rates walk hand in hand and their parallel movements are associated with two variables linked to social integration and regulation

Cohort Variations in Suicide Rates among Families of Nations

29 pagesUsing data on age-specific suicide death rates from 19 modern nations and cohorts born as early as 1875–9, we find that two indicators of cohort-related social capital, relative cohort size and percentage of nonmarital births, are positively and significantly related to suicide rates. These effects are significantly stronger in the English-speaking family of nations, which have historically provided fewer political and social supports to families and children. The analytic model, an extension of the Age-Period Cohort Characteristic model, which utilizes hierarchical linear modeling, provides strong controls for age and period effects as well as for autoregressive effects within cohorts. Our data allow us to include older age groups and data from a wider range of countries than previous studies

Can Cohort Replacement Explain Changes in the Relationship Between Age and Homicide Offending?

23 pagesThis paper focuses on shifts in the age distribution of homicide offending in the United States. This distribution remained remarkably stable with small but significant changes over a long period of time. Then between 1985 and 1990 the rates of homicide offending doubled for 15-to-19 year olds and increased nearly 40% for 20-to-24 year olds, while the homicide offending rates decreased for those over 30. In addition to this ‘‘epidemic of youth homicide,’’ which lasted through the mid-1990s, there have been systematic changes in the age distribution of homicide in the United States associated with cohort replacement over the past 40 years. We introduce an estimable function approach for estimating the effects of age, period, and cohort. The method allows us to assess simultaneously the impacts of periods and cohorts on the age distribution of homicide offending. We find that although the age curve remains relatively stable, there are shifts in it associated systematically with cohort replacement. Cohort replacement accounts for nearly half of the upturn in youth homicides during the epidemic of youth homicides, but a significant fraction of that upturn is not associated with cohort replacement

Cohort Effects on Suicide Rates: International Variations

19 pagesRecently, the long observed pattern of a monotonic increase in suicide with age has shifted, often dramatically, because more recent birth cohorts have exhibited much higher suicide rates at younger ages than earlier cohorts have. These changes, however, did not occur in all countries. We examine cohort variations in suicide rates in 14 modern, western societies using an extension of the age-period-cohort characteristic model that incorporates hierarchical linear modeling. Results support a general Durkheimian perspective. Birth cohorts experiencing relatively less social integration and regulation, as measured by higher rates of nonmarital births and larger relative cohort size, have higher suicide rates than other cohorts. Societies that provide alternative sources of social integration and regulation, as through collectivist institutions or through greater support for families and children, moderate this tendency. On the other hand, when societies experience rapid social change, the relationship between decreased social integration and regulation and increased suicide rates is stronger, especially for males. These results have implications for stemming the increased suicide rates for youth observed in many contemporary societies

Hubble Space Telescope FUV Spectra of the Post-Common-Envelope Hyades Binary V471 Tauri

We have carried out an analysis of the HST STIS archival spectra of the magnetic white dwarf in the Hyades eclipsing-spectroscopic, post-common envelope binary V471 Tauri, time resolved on the orbit and on the X-ray rotational phase of the magnetic white dwarf. An HST STIS spectrum obtained during primary eclipse reveals a host of transition region/chromospheric emission features including N V (1238, 1242), Si IV (1393, 1402), C IV (1548, 1550) and He II (1640). The spectroscopic characteristics and emission line fluxes of the transition region/chromosphere of the very active, rapidly rotating, K2V component of V471 Tauri, are compared with the emission characteristics of fast rotating K dwarfs in young open clusters. We have detected a number of absorption features associated with metals accreted onto the photosphere of the magnetic white dwarf from which we derive radial velocities. All of the absorption features are modulated on the 555s rotation period of the white dwarf with maximum line strength at rotational phase 0.0 when the primary magnetic accretion region is facing the observer. The photospheric absorption features show no clear evidence of Zeeman splitting and no evidence of a correlation between their variations in strength and orbital phase. We report clear evidence of a secondary accretion pole. We derive C and Si abundances from the Si IV and C III features. All other absorption lines are either interstellar or associated with a region above the white dwarf and/or with coronal mass ejection events illuminated as they pass in front of the white dwarf.Comment: The Astrophysical Journal, May 10, 2012 issue - 16 figure

Letter from the Co-editors

2 pagesIn case you missed it, last fall, The American Sociologist published a double issue on the Pacific Sociological Association (PSA). Rare is the opportunity for such open reflection by an organization. Spanning two dozen articles and more than 200 pages, esteemed members, past and present, cast light on where the Association has been and where it is headed. It is good stuff— sociologists reflecting on structures they have created to engage and understand structures in which we are all embedded. And, as you might imagine, a major leitmotif in this effort is change, both inside and outside the organization. We recommend that you check out the issue, if haven’t already. For our purposes, though, we adopt and extend the theme of change—recent and forthcoming—with Sociological Perspectives. Some of it good. Some of it sad. And, some to be determined

The Enduring Effects of Cohort Characteristics on Age-Specific Homicide Rates, 1960–1995

35 pagesIn the past decade, young people in the United States have been two to three times more likely than in the two previous decades to commit homicides, while those 25 years and older have been less likely to commit homicides than were members of their age groups in the earlier time period. These changes in youth homicide rates are associated with two cohort characteristics that are theoretically linked to criminality: relative size of cohorts and the percentage of cohort members born to unwed mothers. These effects persist throughout the life span, are independent of age and historical period, and can explain fluctuations in homicide arrest rates before the recent upturn