On the robustness of x-charts

In process control the simple x-charts are widely used. In determining an optimum economic design for such a control procedure the time of satisfactory production is usually assumed to be exponentially distributed. In this paper deviations from this optimistic approach are investigated by comparing E-optimal x-charts (using the assumption of an exponentially distributed lifetime) and M-optimal x-charts which are obtained by tfie pessimistic muumax principle applied to all possible lifetime distributions with the same mean value. The comparison shows that the differences between E- and M-optimal x-charts are only minor with respect to a suitable loss function and therefore, the model under consideration is verv robust against deviations from the assumption about the distribution of the time of satisfactory production.     

On the Markov property of order statistics

The order statistics from a sample of size n≥3 from a discrete distribution form a Markov chain if and only if the parent distribution is supported by one or two points. More generally, a necessary and sufficient condition for the order statistics to form a Markov chain for (n≥3) is that there does not exist any atom x₀ of the parent distribution F satisfying F(x₀-)>0 and F(x₀)<1. To derive this result a formula for the joint distribution of order statistics is proved, which is of an interest on its own. Many exponential characterizations implicitly assume the Markov property. The corresponding putative geometric characterizations cannot then be reasonably expected to obtain. Some illustrative geometric characterizations are discussed.     

Estimating the immigration multiplier: an analysis of recent Korean and Filipino immigration to the United States

"This article explores the effect of 'chaining' through the petitioning of relatives on the demand for future immigrant visas [to the United States]. The data for the study come from a 1986 survey of 3,911 respondents from the Philippines and the Republic of Korea who were interviewed in Manila and Seoul just after they had received their U.S. immigrant visas. Analyses are conducted to derive different types of multipliers that may be used in estimating the effects of chain migration.... The empirical results for the Philippines and Korea indicate that the potential for future immigration through the family reunification entitlements of the immigration law is lower than has previously been suggested." This is a revised version of a paper originally presented at the 1987 Annual Meeting of the Population Association of America (see Population Index, Vol. 53, No. 3, Fall 1987, p. 385).     

Overseas workers' remittances in Asian development

In recent years, overseas workers from Asia have been sending remittances of about $8 billion annually to their home countries. These remittances are an important source of precious foreign exchange for the major labor-exporting countries. The overall development impact of remittances, however, has not been well established. Remittances are spent primarily on day-to-day consumption expenditures, housing, land purchase, and debt repayment. Although only a small proportion of remittances are directed into productive investments, this does not warrant the conclusion that the developmental value of remittances is negligible. In fact, remittances spent on domestic goods and services Asia provide an important stimulus to indigenous industries and to the economies of the labor supplying countries. It is these broader macroeconomic benefits of remittances which seem to have been largely ignored in the literature, and this perhaps explains the pessimistic view of the developmental value of remittances. Reservations concerning the effects of remittance on the sending countries include the fears that 1) expenditure patterns of remittance receiving households may create a demonstration effect whereby nonmigrant households may increase consumption, 2) remittance inflow will increase income and wealth inequalities, 3) remittance expenditures may result in inflation, 4) remittances may produce only short-term fluctuations in long-term economic development, and 5) remittances may adversely affect agricultural development.     

Governanceregimes im Wandel

Since the early 1990s, substantial changes have been observed in the organizational and decision structures of the non-university research sector. Drawing on a broad spectrum of quantitative and qualitative evidence, we investigate these changes in the governance regimes of the Max-Planck Society, the Fraunhofer Society, the Helmholtz Association and the Leibniz Association. Our analysis shows that the output efficiency of these four research organizations has increased markedly. Also, new governance mechanisms have become stronger, such as hierarchical management, resource competition, network coordination and international reputational competition. In contrast to developments in the university sector, however, we do not find evidence for a decrease in state influence. Rather, the governance regimes of research organizations have become more complex and tend to be “over-steered”.     

Kollegiale Supervision — ein Instrument der Qualitätsentwicklung für die Hochschullehre?

The enhancement of quality inhigher education is an important task for German universities. As this article point out, peer supervision might serve as an important instrument to accomplish this task, if the interchange of ideas on higher education leads to agreements on goals and the development of behavioral standards. Some requirements that should be met to make sure that peer supervision has these effects are described at the end of the article.