NEAREST NEIGHBOUR ANALYSIS OF UNEQUALLY REPLICATED TRIALS

There has been much work on the use of neighbouring plots to control environmental variation in the analysis of agricultural field experiments. In particular, the Residual Maximum Likelihood Neighbour (REMLN) analysis of Gleeson&Cullis (1987) appears very promising. The application of the REMLN analysis to an unequally replicated field trial augmented with an additional variety planted every six plots in a grid system is here compared with a covariance (COV) analysis using the neighbouring grid or check plot values as the covariate. The results indicate that the REMLN analysis gives more accurate estimates of treatment contrasts than the COV analyses, but that the estimate of treatment means can be biased. The bias depends on the mean of the check plot. This bias can be removed by adjusting the estimates of the treatment means such that their average equals the average of the raw means rather than that of the raw data.     

Suicide among elderly white men: development of a profile.

1. Older white men have the highest suicide rate in the nation; a linear increase of suicide occurs with each passing year of chronological age. 2. Elderly who attempt suicide are more likely to communicate their intentions less frequently and to use violent and lethal means. 3. Chronic sleep problems, pain, degenerative illness, or clinical depression may be experienced by older white men at suicidal risk; somatic complaints including imaginary symptoms can mask depression. 4. Educational programs, outreach mental health programs, and enhanced consultation/coordination improve case findings and early intervention. Holistic nursing care, including pain alleviation, depression assessment, and simple comfort measures, are imperative in suicide prevention in the elderly.     

Families and donor insemination: the views of semen donors

One of the consequences of donor insemination for the semen donor is that he becomes a member of two families: his own family in which he has a genetic and social connection with his offspring; and the family of the recipient couple, in which he has a genetic connection to the offspring, but usually no social connection with either the offspring or the recipient couple. This article challenges the dominant view that donor insemination as a practice of mainly medical or legal importance by looking at the attitudes of donors to both their own family and the family to which they have contributed their genetic material. Results are presented concerning who donors have told about their donation, who they think should be told, whether they think recipient couples should tell their donor insemination offspring about their conception, and concerning their opinions about factors that are considered in matching donors with recipient fathers.     

Criteria for judging the credibility of children's statements about their sexual abuse

One hundred and three cases of child sexual maltreatment, where offenders confessed to some level of their abuse, were examined to determine the extent to which the children's statements about their victimization contained three widely accepted clinical criteria of a true sexual abuse allegation. The results support clinical assumptions that the criteria in question were valid ones for determining the truth of a sexual abuse allegation in cases involving confessions of abusers.     

Panel data regression for counts

A new panel data model for count data is introduced. We suggest alternative estimators, such as pseudo maximum likelihood and generalized method of moments, of structural and nuisance parameters. In addition, different test statistics of independence and overdispersion are obtained. The small sample performance of the estimators and tests are evaluated in Monte Carlo experiments. The model is applied to the number of days absent in Sweden 1981–1991 for a panel of Swedish male workers.     

Interrelationships between fertility and marital dissolution: Results of a simultaneous logit model

Previous studies have failed to examine (a) the simultaneity of decisions to bear children and to dissolve a marriage and (b) the effects of the childbearing in the period just before dissolution on the likelihood of disruption. We attempted to resolve both problems by developing a simultaneous logit model of the interrelationship between the probability of separation and of having a birth during this period (when dissolution presumably is being considered). The model was estimated at successive durations of first marriage, using data for white women in the 1970 National Fertility Survey. The results indicate that childbearing patterns— number of children and age of youngest child at the beginning of the marital interval being studied and fertility during the interval—did not influence the likelihood of separation in simple or consistent ways over the marital life course, nor did marital strife (as indicated by separation) seem to affect childbearing throughout marriage.     

Family violence: A microeconomic approach

A model of violence between adult family members is developed by integrating material from the sociological theories of family violence and social exchange, and the economic theories of crime and the family. Based on this model a decrease in the dictator's internal sanctions against violence would be expected to increase the amount of time allocated to violence by the dictator. Further, if the level of fines and other monetary costs imposed by external agencies (e.g., the courts) as a result of the family violence do not vary with the level of violence, then the model indicates that an increase in such monetary sanctions will cause a reduction in the amount of time the dictator allocates to violence. If both the dictator and victim are risk neutral, an increase in the probability of external intervention will decrease the time allocated to violence. In addition, it is found that increases in the opportunities available to the victim outside the marriage will tend to improve the well-being of the victim in the marriage even if it has no effect on the time allocated to violence by the dictator. The model also provides insights for empirical work in family violence such as (1) suggestions of relevant independent variables, (2) the specification of a functional form for estimation, and (3) the specification of an error structure for the empirical model.     

Judgments of the Carter-Reagan Debate: The Eyes of the Beholders

In line with social-psychological theory and with findings fromprior analyses of the impact of televised campaign debates,the 1980 Carter-Reagan debate seems to have been interpretedlargely in light of preexisting candidate preferences. Knowledgeof whether a viewer intended to vote for Carter or Reagan and,for undecided voters, knowledge of position on the liberal-conservativecontinuum, permit accurate predictions to be made of judgmentsof who won the debate.     

Dependent masking and system life data analysis: Bayesian inference for two-component systems

Data from field operations of a system is often used to estimate the reliability of components. Under ideal circumstances, this system field data contains the time to failure along with information on the exact component responsible for the system failure. However, in many cases, the exact component causing the failure of the system cannot be identified, and is considered to be masked. Previously developed models for estimation of component reliability from masked system life data have been based upon the assumption that masking occurs independently of the true cause of system failure. In this paper we develop a Bayesian methodology for estimating component reliabilities from masked system life data when the probability of masking is dependent upon the true cause of system failure. The Bayesian approach is illustrated for the case of a two-component system of exponentially distributed components.     

Longitudinal measurement models in evaluation research: Examining stability and change

This article provides an introduction to the use of Confirmatory Factor Analysis to test measurement invariance and stability in longitudinal research. The approach is illustrated through examples representing: (a) one construct, two measurement waves; (b) one construct, three waves; (c) two constructs, two waves; and (d) comparison of treatment and control groups in pre-post designs. Basic issues in establishing measurement invariance over time, across treatment groups, and within measurement waves are discussed. Estimates of the stability coefficients that are corrected for measurement error and method variance associated with each specific measured variable are provided. Establishing measurement invariance is a critical requirement for making inferences about treatment effects and changes in constructs over time.