Parental survival data: Some results of the application of Ledermann's model life tables

Summary Ledermann's one- and two-parameter model life tables are used in order to summarize and compare adult mortality estimates derived from parental survival data, and also to link parental survival with child survival data. The Ledermann models provide an alternative to the logit model used by Brass and Hill. Examination of life tables derived from actual child and adult mortality estimates reveals that although the two types of models yield similar overall levels of mortality, they show marked differences in the estimated patterns by sex and age. It has not been possible to disentangle completely how much of this divergence is due to the models themselves and how much to inadequacies in the data available. Finally, we question whether it is always wise to establish a full life table from child and adult mortality estimates when these are based on data which refer to different periods of exposure to the risk of dying, without allowance for possible distortions resulting from mortality change.     

Reducing Refusal Rates for Telephone Interviews

In two experiments, refusal rates to telephone interviews werenot affected by substantial changes in the introductory remarksof the interviewer. A prior letter significantly lowered refusalrates in a third experiment. In all three, interviewer sex hadno effect.     

Multiproblem families: A social-psychological perspective

Summary It is generally conceded that our allied mental health professions have fallen short in our attempts to provide adequate services to those people whose need is most desperate, those individuals and families ambiguously and condescendingly designated multiproblem. It could be said that we, the caregivers, have been unwilling or unable to be good enough mothers to these, our motherless children. In fact, the early, formative experience of the people with whom we are concerned has invariably been marked by gross discontinuities in mothering; the consequent defects in controlling, regulatory psychic structure (ego defects) are most prominently manifested in the chaotic life-style which characterizes these individuals and families. Our task as caregivers, when viewed from this perspective, is clear: we must somehow bring order out of disorder. But, with tragic regularity, disorder prevails; the provider of service succumbs to the same painful feelings of disorganization, bewilderment, frustration, and helplessness with which his client struggles, and, eventually, both give up in despair. What is more, this sense of fragmentation and futility pervades the institutions responsible for provision of services. Client, caregiver, and institution, all are trapped in the same tortuous maze. How, then, are we to extricate ourselves? Certainly not by drafting yet another master plan which promises everything and delivers nothing. Both realistic and humanistic considerations dictate more modest goals: We might not be able to rescue everyone who needs assistance, but we can help a few. And, whatever approach we may adopt, the service we offer can only be effective if it is based upon a sustained and sustaining (in essence, maternal) relationship.Sometimes I Feel Like a Motherless Child     

On the Critical Value Behaviour of Multiple Decision Procedures

In this paper we investigate the asymptotic critical value behaviour of certain multiple decision procedures as e.g. simultaneous confidence intervals and simultaneous as well as stepwise multiple test procedures. Supposing that n hypotheses or parameters of interest are under consideration we investigate the critical value behaviour when n increases. More specifically, we answer e.g. the question by which amount the lengths of confidence intervals increase when an additional parameter is added to the statistical analysis. Furthermore, critical values of different multiple decision procedures as for instance step-down and step-up procedures will be compared. Some general theoretic results are derived and applied for various distributions.     

Effects of sterile insect releases on a population under predation or parasitism

Summary A continuous-time differential equation model was constructed which describes the population dynamics of a predator prey system in which sterile prey are released in a program designed to eradicate or reduce the prey population. It was found that the dynamics of the system behave quite differently when predators are present. Two conditions were found which have differing implications for the control program. If the predators still exist when the wild prey population declines to extinction, then the SIRM is assisted by the predators, sometimes to a considereble extent. If the predators decline to extinction before the wild prey population goes extinct, then the predators may or may not assist the SIRM depending on the parameters of the system. If the predators do assist the SIRM, then a potentially dangerous situation exists in which an explosion of the prey population could occur after the predators go extinct. Predator polyphagy would probably minimize this danger of an explosion since it would stabilize the predator population.