Some results on optimality in models with heteroscedastic errors from partial optimum designs

This paper studies optimum designs for linear models when the errors are heteroscedastic. Sufficient conditions are given in order to obtainD-, A- andE-optimum designs for a complete regression model from partial optimum designs for some sub-parameters. A result about optimality for a complete model from the optimality for the submodels is included. Supported by Junta de Andalucía, research group FQM244.     

A “brer rabbit” case for reverse mandated benefits

Reverse mandated benefits is a government-mandated policy that requires employees to provide their employers with benefits that workers would not provide otherwise. Of course, only those benefits would be mandated that are worth more to employers than they cost, as determined by political authorities. My case for such a policy argues that it is at least as sensible as policies mandating that employers provide benefits to their employees that would not be provided otherwise.     

Effects of Category Order on Answers in Mail and Telephone Surveys1

Abstract Past research suggests that mail surveys encourage a primacy effect, which is a tendency to choose the first answers from a list, whereas telephone surveys encourage a recency effect, a tendency to choose the last answers from a list. This paper summarizes results from 82 new experiments conducted in 12 separate surveys in seven states. Only four of 33 mail survey comparisons exhibited significant primacy effects, while five of 26 experiments in telephone surveys exhibited recency effects. In addition, only three of 23 cross-method comparisons produced a significant primacy/recency effect in the expected manner. The conclusion is that the prevalence of primacy and recency effects has been over-estimated by past research and a new theoretical approach that takes into account multiple causation is needed for examining these effects.     

Expected sample moments of concomitants of selected order statistics

In this paper, the task of determining expected values of sample moments, where the sample members have been selected based on noisy information, is considered. This task is a recurring problem in the theory of evolution strategies. Exact expressions for expected values of sums of products of concomitants of selected order statistics are derived. Then, using Edgeworth and Cornish-Fisher approximations, explicit results that depend on coefficients that can be determined numerically are obtained. While the results are exact only for normal populations, it is shown experimentally that including skewness and kurtosis in the calculations can yield greatly improved results for other distributions.     

Compulsive gambling and the medical model

The medical model as a conceptual and operative approach to compulsive gambling is discussed. The terms medical model and disease are defined and the practical implications of their application to compulsive gambling are explored. Special attention is given to the addictive disease concept. Finally, a variety of objections to the medical model are described, but it is concluded that the many individual and social advantages of the medical model make it the preferred conceptualization at our present state of knowledge.     

Policies and strategies for integrating women in agriculture and rural development

Continued economic stagnation, civil unrest, rural-urban migration, and a series of natural disasters have impeded efforts in the Sudan to integrate women into the development process. Although the Four-Year (1988-1989 to 1991-92) Salvation, Recovery, and Development Programs Plan does not explicitly addresses women's issues, its emphasis on food security, appropriate technology for the agricultural sector, small-scale industries and handicrafts, balanced regional development, and the needs of the poorest 20% of the population guarantees that women will be major recipients. There remains a need, however, to increase women's participation in the development planning process and to base projects on reliable data on women's economic activities. More successful in defining women's needs have been community development projects--Western Savannah Development Corporation, Blue Nile Integrated Rural Development Project, Nuba Mountain Project, and Jebel Marra Rural Development Project--that combine income generation, social welfare, and agricultural research. It is recommended that all such large integrated rural development or agricultural projects allot funds specifically for women's activities and ensure coordination with women's organizations to avoid duplication and identify areas of greatest need. Also urged is the development of appropriate technologies that will alleviate women's double burden of poverty and household chores and address the inequitable distribution of income. Establishment of a women's bureau for women's affairs and development within the National Planning Department would facilitate project formulation and evaluation. In need of change if women in development projects in the Sudan are to be successful are laws that limit female land ownership and practices that deny women loans and credit.     

Return migration from Australia: a case study

"The study investigates the departure from Australia of former settlers who arrived during the 1980 calendar year. The 1980 settler arrival cohort [consists] of 75,167 visaed migrants.... The study has three main aims: (i) to analyse departures from Australia of the 1980 settler arrival cohort with a view to gauging the success of Australia's immigration program in retaining settlers; (ii) to examine the retention rates of settlers with respect to characteristics...including age, sex, marital status, country of last residence, and settler eligibility category; and (iii) to consider implications of the findings." Australia's present immigration policy is discussed, previous research on return migration from Australia is summarized, and a detailed analysis of the departure data is presented. "This study found that by August 1984, 12.4 per cent of non-refugee settlers who arrived in Australia during 1980 had departed permanently but that only 0.6 per cent of the 1980 refugee cohort had done so." These figures represent a decline in immigrant departure rates since the 1960s and early 1970s. Small differences in departure rates by place of birth, age, and marital status, which may have demographic consequences if sustained over time, are noted. (SUMMARY IN FRE AND SPA)     

Migration of the rural population under conditions of agro-industrial integration

Factors affecting rural-urban migration in the USSR are examined. The author suggests that a lower rate of such migration is associated with the creation of agro-industrial centers.     

Pluralism and ethnic conflict in Tanzania's arid lands: the case of the Maasai and the WaArusha

In Tanzania, the Maasai and Waarusha tribes are experiencing conflict because differences in their modes of productions and economic strategies undermine the peaceful coexistence that they have enjoyed since the 18th century. The Maasai are pastoralists, while the Waarusha are agricultural subsistence farmers who are encroaching on the best pasture lands. A sketch of the history of the two groups shows that the Maasai reached the peak of their land holding in 1880 before the arrival of European colonists who seized land and restricted the Maasai to a semi-arid reserve but allowed the Maasai to remain an autonomous and powerful group. The Waarusha began encroaching on Maasai land after independence due to land and population pressure. While closely tied, each group looks down on the other, and Maasai ascendancy has given way to Waarusha challenges. After independence, the tribal and ethnic rule that was protected by the colonial system was disrupted to allow for increased internal migration and new patterns of settlement. The rights of land ownership were transferred from tribes to the State, allowing privileged groups to benefit. The Waarusha began to engage in illegal land-grabbing and to encroach on the Maasai preserve using legal and illegal means. The Maasai view land as collective property and have had difficulty retaining title of traditional lands in the face of population pressure. This loss of grazing land has forced the Maasai into a mixed economy that depends upon agricultural production as well as livestock production. In the meantime, the Waarusha have deliberately sought political office to gain power to secure their holdings. Immediate action is needed to produce 1) a policy on spontaneous settlement, 2) an immediate adjustment of legal procedures for land acquisition, 3) a land tenure policy that equally emphasizes agricultural and livestock production, and 4) controls on undue expansion of subsistence agriculture into semi-arid rangelands.