Estimating chance reproducibility in Guttman Scaling

A definition of reproducibility in Guttman Scaling and two chance measures of reproducibility are suggested. The first measure assumes that the items are independent. The second method assumes nonindependent items and fits respondent and item margins by an iterative method used in fitting log-linear models. Chance reproducibility is conceptualized in terms of assumptions about respondent variability.     

Social Contacts Amongst Suburban Housewives

Popular or media portrayals have suggested that many suburban housewives are dissatisfied with a number of aspects of their lives. This claim was investigated by surveying two groups of Brisbane women. Data obtained firstly from a sample at a shopping town and secondly from the members of a women's social club suggests that the dissatisfaction with the role of housewife expressed in the media may be overstated. Women find a lack of social contacts with others to be acute but report satisfaction with other aspects of their lives. Tentative solutions to facilitate social contacts between women are suggested.     

Family size and children’s education in Vietnam

Data from the nationally representative 1994 Inter-Censal Demographic Survey are used to examine the association between family size and children s schooling in Vietnam. The data provide information on several education measures for all children over age 10, including children no longer residing in the household. Although a clear inverse bivariate association between family size and children s school attendance and educational attainment is evident, multivariate analysis controlling for urban/rural residence, region, parents’ education, household wealth, and child’s age, reveals that much of this association, especially that predicting educational attainment, is attributable to these other influences. Moreover, much of the effect that remains after statistical adjustment for the other influences is seen mainly at the largest family sizes. We consider the implications of these findings for current population policy in Vietnam and the possible features of the Vietnamese context that might account for the modest association.     

Making Sense of the Census: Why Sampling Might Not Be so Simple

Population and Environment -     

Effects of Group Practice of the Transcendental Meditation Program on Preventing Violent Crime in Washington,D.C.: Results of the National Demonstration Project,June--July 1993

This paper reports the results of a prospective experiment in which a group of approximately 4,000 participants in the Transcendental Meditation and TM-Sidhi programs of Maharishi Mahesh Yogi assembled in Washington, D.C., from June 7 to July 30, 1993. It was hypothesized that levels of violent crime in the District of Columbia would fall substantially during the Demonstration Project, as a result of the group's effect of increasing coherence and reducing stress in the collective consciousness of the District. A 27-member Project Review Board comprising independent scientists and leading citizens approved the research protocol and monitored the research process. Weekly crime data was derived from database records provided by the District of Columbia Metropolitan Police Department (DCMPD), which are used in the FBI Uniform Crime Reports. Statistical analysis considered the effect of weather variables, daylight, historical crime trends and annual patterns in the District of Columbia, as well as trends in neighboring cities. Consistent with previous research, levels of homicides, rapes and assaults (HRA crimes) correlated with average weekly temperature. Robberies approximately followed an annually recurring cycle. Time series analysis of 1993 data, controlling for temperature, showed that HRA crimes dropped significantly during the Demonstration Project, corresponding with increases in the size of the group; the maximum decrease was 23.3% (p < 2 × 10–9) [24.6% using a longer baseline, with 1988--1993 data (p < 3 × 10–5)], coincident with the peak number of participants in the group during the final week of the assembly. When the same period in each of the five previous years was examined, no significant decreases in HRA crimes were found. Robberies did not decrease significantly. However, a model that jointly estimated the effect of the Demonstration Project on both HRA crimes and robberies showed a significant reduction in violent crimes overall of 15.6% (p = 0.0008). Further analysis showed that the effect of the coherence-creating group on reducing HRA crimes could not be accounted for by additional police staffing. The time series analysis for HRA crimes gave results that are highly robust to alternative model specifications, and showed that the effect of the group size was cumulative and persisted after the Demonstration Project ended. Also, calculation of the steady state gain based on the time series model predicted that a permanent group of 4,000 coherence-creating experts in the District would have a long-term effect of reducing HRA crimes by 48%.     

Preference in flower visits and partitioning in pollen diets of stingless bees in an Asian tropical rain forest

Floral resource partitioning among stingless bees (Trigona, Meliponini, Apidae) in a lowland rain forest in Sarawak, Malaysia, was investigated using tree towers and walkways in a 4-year study that included a general flowering period. We obtained 100 collections of insect visitors to flowers of varying floral location and shape representing 81 plant species. The tendency of 11 species of stingless bees to visit specific flowers with a particular floral location and shape was analyzed by logistic regression analysis. This analysis showed that the proportion of flower visitor collections containing Trigona fuscobalteata and T. melanocephala differed according to floral location. The former was frequently collected at canopy and gap flowers, whereas the latter was most often collected at understory flowers. The analysis also suggested that T. erythrogastra was more rarely collected at shallow flowers than at deep flowers. Analysis of the pollen diets of T. collina, T. fuscobalteata, T. melanocephala, and T. melina revealed that similarity of pollen sources differed among the six permutated pairs of the four species. The lowest mean rank of similarity found was between T. fuscobalteata and T. melanocephala. This result supports the hypothesis that preference in visiting flowers in different locations leads to pollen resource partitioning. Received: May 14, 1997 / Accepted: April 23, 1999     

Entry or exit? A transition-probability approach to explaining the high prevalence of single motherhood among black women

I analyze the prevalence of single motherhood among black and non-Hispanic white women in terms of differences in entry and exit. Higher initial entry rates among black women, especially through unpartnered childbearing, account for slightly more than half the difference between blacks and whites in the prevalence of single motherhood. The remainder of the difference is due to black single mothers' much lower rates of exit through union formation and to their very high rates of reentry through dissolution of these later unions. Entry and exit rates through the 1990s imply a widening racial gap.     

Retrospective information on health status and its application for population health measures

Healthy life expectancies are almost always calculated by using health data from cross-sectional surveys. This type of calculation is done partly because data from longitudinal surveys are not always available, and when they are available, they are collected at intervals that are longer than one year. In such cases, collecting health information retrospectively for the years skipped by the survey is useful. The main purpose of this paper is to show how retrospective health information can be used to estimate life expectancies in different health states. Healthy life expectancies are estimated with and without using data on retrospective health information, and the corresponding estimates are compared. The two sets of estimates are similar. We conclude that retrospectively assessed health information based on a one-year recall period can be used to estimate years of life in various health states and that estimates based on such information will closely approximate estimates based on concurrent health information.