A maximum-likelihood estimator with infinite error

The standard error of the maximum-likelihood estimator for 1/μ based on a random sample of size N from the normal distribution N(μ,σ²) is infinite. This could be considered to be a disadvantage.Another disadvantage is that the bias of the estimator is undefined if the integral is interpreted in the usual sense as a Lebesgue integral. It is shown here that the integral expression for the bias can be interpreted in the sense given by the Schwartz theory of generalized functions. Furthermore, an explicit closed form expression in terms of the complex error function is derived. It is also proven that unbiased estimation of 1/μ is impossible.Further results on the maximum-likelihood estimator are investigated, including closed form expressions for the generalized moments and corresponding complete asymptotic expansions. It is observed that the problem can be reduced to a one-parameter problem depending only on , and this holds also for more general location-scale problems. The parameter can be interpreted as a shape parameter for the distribution of the maximum-likelihood estimator.An alternative estimator is suggested motivated by the asymptotic expansion for the bias, and it is argued that the suggested estimator is an improvement. The method used for the construction of the estimator is simple and generalizes to other parametric families.The problem leads to a rediscovery of a generalized mathematical expectation introduced originally by Kolmogorov [1933. Foundations of the Theory of Probability, second ed. Chelsea Publishing Company (1956)]. A brief discussion of this, and some related integrals, is provided. It is in particular argued that the principal value expectation provides a reasonable location parameter in cases where it exists. This does not hold generally for expectations interpreted in the sense given by the Schwartz theory of generalized functions.     

Childbearing after Migration: Fertility Patterns of Foreign‐born Women in Sweden1

The present study provides an investigation of patterns in childbearing among foreign‐born women in Sweden from the 1960s to the 1990s. Event‐history techniques are applied to longitudinal population register data on childbearing and migration of 446,000 foreign‐born women who had ever lived in Sweden before the end of 1999. Period trends in parity‐specific fertility appear to be quite similar for Swedish‐ and foreignborn women, but important differences exist in levels of childbearing propensities between women from different countries of origin. Most immigrant groups tend to display higher levels of childbearing shortly after immigration. We conclude that migration and family building in many cases are interrelated processes and that it is always important to account for time since migration when fertility of immigrants is studied.     

The Impact of Labour-Force Participation on Childbearing Behaviour: Pro-Cyclical Fertility in Sweden during the 1980s and the 1990s

During the last two decades, Sweden has experienced strong fluctuations both in its economy and in its level of childbearing. A period of high employment and increasing fertility has been followed by a period of lower employment and decreasing fertility since the beginning of the 1990s. In this paper, we use register data for Swedish women in order to examine how various types of attachment to the labour market affect women's propensity to give birth at different parities. Specifically, we show what impact changes in women's employment status have had on recorded fertility trends in Sweden. We find that women who have relatively low levels of income and women who are enrolled as students generally have lower fertility than other women. We also find that a rise in the number of women with such characteristics can explain part of the decrease in fertility during the 1990s. It is evident, however, that other factors, working at the macro level, also have to be considered when one wants to explain the fluctuating fertility of Sweden. Social policy is one such factor. In sum, we find a pattern of pro-cyclical fertility, where levels of female earnings are positively related to levels of childbearing.     

Childbearing Trends in Sweden 1961--1997

The purpose of this paper is to update a system of annual indices of birth rates and to display trends in childbearing for Swedish women over the years since 1961. Our indices are produced by applying indirect standardization to register data. They enable us to decompose the overall fertility trends, as measured by the period TFR, into its birth-order specific components. Swedish fertility has shown strong fluctuations during our study period and these fluctuations have been particularly dramatic during recent years. A postponement of the age at first birth and a sudden shift to shorter birth intervals are important components in the fertility trends. A peak in the level of childbearing at the beginning of the present decade has now been followed by a sharp drop in the propensity to give birth. This change in behaviour pertains to women of all parities.     

Varieties of Democracy: Interest Groups and Corporatist Committees in Scandinavian Policy Making

Corporatism may be seen as variety of capitalism in which specific structural prerequisites such as unionization, centralization, and strong states combined with bargaining and concertation produce certain economic outputs. Corporatism may also be seen as a variety of democracy in which interest groups are integrated in the preparation and/or implementation of public policies. Departing in the last position, we measure the strength of Scandinavian corporatism by the involvement of interest groups in public committees, councils, and commissions. Corporatism in relation to the preparation of policy has gone down in all three Scandinavian countries whereas corporatism in implementation processes are more varied among the three countries.     

Sex composition of children as a determinant of marriage disruption and marriage formation: Evidence from Swedish register data

This paper investigates the effect of sex composition of children on the propensity of Swedish mothers to enter and leave marriage. Swedish population-register data are used to estimate relative risks of marriage formation and marriage dissolution for mothers with different numbers and sexes of children. The large number of observations allows us to get a very accurate picture of such relationships even if they are relatively weak. Morganet al. (1988) used survey data for the US and claimed to have found that one- and two-child parents in that country had lower divorce risks if they had sons than if they had daughters. For Sweden, we find only a minor effect in the same direction for three-child mothers. For two-child mothers, we instead find that the divorce risk is slightly reduced if a woman has one child of each sex. The divorce risk of one-child mothers is not at all affected by the sex of the child. Finally, the sex composition of children has no effect on the propensity of Swedish mothers to enter the married state.     

Visual challenges using Visual Display Units (VDU) in office landscapes

A total of 85 VDU operators, in three main Scandinavian Alcatel-Lucent headquarters, were followed in a process moving from single occupancy offices to an office landscape. This paper discusses the visual challenges and implications in such a transfer. In the oral presentation recommendation on how to avoid visual problems will be given.